Response on my post comparing sensors

Discussion in 'Canon EOS' started by brent_bennett, Jun 6, 2011.

  1. To all who responded on my question about sensor quality of Canon vs. Pentax, Sony and Nikon:
    Thank you for your responses. I didn't expect to have so many make negative comments about DxOMark, especially when I didn't mention it by name. I think the best response from my point of view is the one from
    Laurentiu. Those who bash the DxOMark testing have not, to my knowledge, suggested an alternative. Does anyone know of any other testing organization that attempts to make similar tests, but does so with more general approval?
    I have never appreciated comments like "tack sharp". I am more analytical by nature, so the DxOMark service appeals to me. And I look at lens tests to make choices on lenses.
    I am fully aware that there are many other feature issues that must be considered in making a decision on which camera to buy. I started with the sensor issue, because as a film photographer for several decades, it is the most obvious feature that I look at. I have never owned or used a digital camera! But I plan on buying one this year. I will be using it for pictures of people and some use in astrophotography. Perhaps eventually using it for landscape as well. Of course I should buy a full-frame or larger, but I don't wish to spend the required higher cost at this time.
    I do landscape photography in prints as large as 24x36. With film cameras from 35mm to 4x5, I have never had to choose a camera based on sensor limits. So this is a new experience for me. It is from that perspective that I asked the question.
    Maybe I should start with a cell phone camera! (just joking)
    Again, thank you all for your thoughts.
     
  2. I do landscape photography in prints as large as 24x36. With film cameras from 35mm to 4x5, I have never had to choose a camera based on sensor limits. So this is a new experience for me. It is from that perspective that I asked the question.​
    It's good that you've told us that landscape photography is your primary application, Brent. But, since that's the case, why are you considering a crop body at all?
    Just pick up a 5DII, and stop worrying about whether the Pentax sensor may or may not have lower noise at high ISO's than the latest Canon crop sensor. There are DSLR's that have (marginally) better high ISO performance than the 5DII, and there are bodies with (marginally) more resolution, but none combines low light capability with high resolution as well as the 5DII does. Just ask experienced landscape photographers (such as photo.net member G Dan Mitchell) which body they use.
     
  3. As mark says - for landscape go full frame. This gives better quality, great high ISO performance (although I rarely find I need it for landscapes) and the best range of wide angle lenses. Going full frame gives you basically two choices - Canon or Nikon and either will serve you well. Sony makes full frame bodies but they have a limited lens range. Thus the best option is probably a 5DII or D700
    A camera like the 5DII with some good glass (you should consider the Canon T/S lenses like the 17F4 or 24 F3.5 II) will serve you well. You should also consider using your MF lenses with an adaptor (especially a tilt / shift one). This is a low cost way to get great results and a good lens selection.
    You suggest that you cannot afford to go full frame but the difference is not that big and you should consider waiting until you can. I have a 7D body and it is a fine camera but I rarely shoot landscapes with it as I find it a less satisfying experience.
    I read your DXO mark post on the K5 but wonder about their tests. I will post a chart to show my issue - it compares the S/N ratio of the K5 with the D3X and 5DII. Up to 1600 ISO the K5 clearly trails but beyond this it improves to be as good or better than the other two bodies. However, coincident with this step increase in performance the data on the K5 changes from actual to smoothed. I am not sure of their methodology but a change in data interpretation coupled with a change in performance does look suspect. You similar with Tonal Range and colour sensitivity. While I have no doubt that DXO Mark is objective the K5 does seem to benefit from some unusual testing approach compared to the other bodies. I also find that their tests do not tell you anything about the image quality - just the performance of the sensor.
    http://dxomark.com/index.php/Camera-Sensor/Compare/Compare-sensors/(appareil1)/676|0/(appareil2)/485|0/(appareil3)/483|0/(onglet)/0/(brand)/Pentax/(brand2)/Nikon/(brand3)/Canon
     
  4. DXO isn't exactly wrong about stuff, but you have to understand the methodology and how they come up with their rankings. Just because a number is assigned to something and the number is higher than the number assigned to some other thing does not automatically make it better. A problem is that quite a few people understandably simply want to have a value that ranks things in order of good, better, best - but it isn't at all that simple.
    In this case, especially if the OP wants to print landscape photographs at 24" x 36" on a regular basis, the "best" choice probably comes from among one of the high MP full frame bodies from Canon, Nikon, or Sony. (Here I presume that the OP is not in the market for digital MF or digital mini MF systems.) With any of these systems excellent print quality is available and things like noise are basically not an issue for this type of work.
    Dan
     
  5. DxOMark is pretty upfront about the limitations of what they gather and how to use their data (and not use their data). They also are pretty clear that just looking at sensor data is not "the" factor in making a decision on a camera:
    http://dxomark.com/index.php/Learn-more/DxOMark-scores/Sensor-scores
    Unfortunately, they set themselves up because these stated limitations of their data are buried in their note in this link and the their online comparison tools allow comparisons way outside the realms of what even DxOMark recommends for a good comparison.
     
  6. G. Dan:
    What is their methodology for determining the scores? Is it actually published anywhere?
     
  7. At the end of the day it's all about the image you want. For most users, the differences between any of the DSLR's, regardless of whether its from Canon, Nikon, Pentax. Sony,etc. is negligible. For the pros, getting the right shot is less about which sensor to use but more about having the right gear and using light effectively. If you sell your photos, no one is going to ask what camera you used.
     
  8. If you sell your photos, no one is going to ask what camera you used.​
    Good point by Alex
    -
    -
    What is their methodology for determining the scores? Is it actually published anywhere?​
    They don't publish much directly. Here is an example: http://dxomark.com/index.php/en/Our-publications/DxOMark-Insights/Detailed-computation-of-DxOMark-Sensor-normalization
    They do sell their evaluation system and offer to provide details about it. Here is a link to their product offering:
    http://www.dxo.com/intl/image_quality/dxo_analyzer/analyzer_overview
     
  9. "If you sell your photos, no one is going to ask what camera you used."
    A nice idea, but not accurate. Many image buyers have equipment specific criteria. I have run into sensor size, format and MP count rejections.
    For the vast majority of users there is virtually no difference between equal generation equipment, and only small differences that are easily adjusted for in post between subsequent generations.
    For somebody wanting to print landscapes regularly to 24" x 36", the very smallest format to be considering is a 135 format digital. Crop cameras, despite the earnest comments some might make, just doesn't cut it.
     
  10. Scott, there are a very small number of buyers/licensors who will specify a MP dimension (e.g. "12MP file") and an even smaller number who will specify a specific format, but these are a very small percentage of the sales opportunities. I can't say that I have encountered a buyer/licensor who wanted to know what brand of camera I used.
    The real question turns out to be "will this work for the use I have planned?"
    Regarding the DXO methodology, I haven't checked since their first round of rankings, what, a couple years back. I recall a post at Luminous Landscape that went into some detail about what the rankings actually meant, though I have to say I have not looked since then.
    Dan
     
  11. zml

    zml

    Brent: The best "testing organization" is you... High(er) end equipment is easy to rent and that's the route a thinking person should take. Take the cost of equipment as a rough guide (i.e. more expensive = better, however you define the word "better"), shell out a few clams for rental and test a variety of rigs in your price range. You may need to learn a bit of post processing (easier, less involving and less time consuming than with film but still...) so you can draw meaningful conclusions. And perhaps 35 mm digital is not for you and you'll choose MF digital but you'll never know unless you test.
    As an aside, among many cameras I shoot with, and I can use any camera in existence, Canon 1Ds Mk. III is a standout. Not something that DxO agrees with...
     
  12. I find DxO to be somewhat useless for a lot of the reasons stated above. I find sites that post consistent photo test
    subjects to be a much better guide, I can compare somewhat similar photos and see a difference or not. Photography
    is a complex subject when you get down to the pixel level. Any quantitive number you assign is at best a single point
    along a continuum, some times in several dimensions. IMO any averaing/summation/analysis introduces subjectivism
    that may not relate to my needs or values. So, yes, a number is great to have, but after using them for a while you
    see how useless they are.

    Full frame 35mm or MF digital. IMO MF digital is the better choice because they usually do not have AA filters over
    the sensor. One day when the digital Genereations slowdown some I may purchase a MF digital. That is pretty far off
    into the future give the price of MF digital.
     
  13. As an aside, among many cameras I shoot with, and I can use any camera in existence, Canon 1Ds Mk. III is a standout. Not something that DxO agrees with...​
    It's actually in the top 10 of their ranking. I would say they agree it has a top sensor.
    And here is the disclaimer that accompanies their sensor reviews:
    This dxomark review evaluates only the selected camera’s RAW sensor performance metrics (i.e., Color Depth, Dynamic Range, and Low-Light ISO), and should not be construed as a review of the camera’s overall performance, as it does not address such other important criteria as image signal processing, mechanical robustness, ease of use, flexibility, optics, value for money, etc. While RAW sensor performance is critically important, it is not the only factor that should be taken into consideration when choosing a digital camera.​
     
  14. I will post a chart to show my issue - it compares the S/N ratio of the K5 with the D3X and 5DII. Up to 1600 ISO the K5 clearly trails but beyond this it improves to be as good or better than the other two bodies. However, coincident with this step increase in performance the data on the K5 changes from actual to smoothed. I am not sure of their methodology but a change in data interpretation coupled with a change in performance does look suspect. You similar with Tonal Range and colour sensitivity. While I have no doubt that DXO Mark is objective the K5 does seem to benefit from some unusual testing approach compared to the other bodies.
    (link)
    Note that the main differences in the performance of those sensors are noticeable at low ISO, not in the areas where the K-5 curve is marked as smoothed:
    • K-5 High ISO score is lower than that of the other two cameras - SNR graph is below the others
    • D3x has highest color depth - its graph is over that of the other two cameras
    • 5DII dynamic range is lower than that of the other two cameras - its DR graph is below others
    Everything is consistent. Notice how the graphs get closer at higher ISO - the large differences are at base ISO.
    As for what is the deal with the smoothed portions of the Pentax graphs - they are explained here: http://www.dxomark.com/index.php/Our-publications/DxOMark-reviews/DxOMark-review-for-Pentax-cameras. So, the smoothed curve just indicates those areas in which dxomark has detected a level of noise reduction present even in RAW files (normally, NR occurs during RAW processing). So instead of measuring IQ with that NR effect, they used some interpolation to estimate the performance if that NR wouldn't be present. But it doesn't really matter, because like I said, the score of the sensor is predominantly determined by performance at low ISO. You're not going to see a camera with a high score in a dimension where its graph is trailing at base ISO.
    I also find that their tests do not tell you anything about the image quality - just the performance of the sensor.​
    I'm not sure what you mean by IQ, because dynamic range, color depth, and SNR are big parts of IQ and DxO makes it clear in their disclaimer that they only test the sensor and that's only one aspect of getting a camera. As for sharpness, chromatic aberrations, distortion, vignetting, etc - those are covered in their lens reviews. Really, it's hard to be more thorough than these guys.
    As for the original question on what camera to get, I would check sensors (dynamic range score for landscape photography), lens lineups, camera features - the whole deal. For example, K-5 has great DR, but probably you can get a wider choice of wide angle lenses on a FF camera, so now you should guide your search within the realm of the FF cameras and the brands that offer you the focal lengths that you want. But the scores can help guide your search and narrow down options, even if they don't outright pinpoint the most suitable camera.
    One important thing that should be obvious, but maybe it's not: dxomark scores are only useful if you intend to shoot RAW. For JPEG shooters, they are truly irrelevant.
     
  15. zml

    zml

    It's actually in the top 10 of their ranking. I would say they agree it has a top sensor.​
    Another way of looking a it is that 1Ds3 is behind all three Nikon D3 models, its only competition. (Which to me, having used all 4 cameras, seems ludicrous.)
     
  16. Laurentiu. You are obviously a big believer in DXO mark so perhaps you can explain the following:

    DXO mark rates the K5 above the 5D II at almost every ISO yet they claim the 5DI can shoot sports at ISO 1815 while
    the K7 can only shoot at 1162. Leaving aside the fact that this is obviously a calculation (unless you use ISO 162) I
    am baffled how the lower noise sensor is over 1/2 a stop worse.

    Most reviews rate the 5D II above the K5 even the lab tests, for example:

    Popular photography tested the 5D II with higher resolution, better colour accuracy, and superior noise performance at
    the tested ISOs

    Dpreview staters that the K5 and 7D noise performance is similar and if you compare the coin tests between the K5
    and 5DII (e.g. ISO100, RAW and no noise reduction the 5D II crop is clearly better)

    I have not seen any landscape shots published from the K5 but I have seen hundreds from the inferior 5D II and 1Ds
    III
     
  17. DXO mark rates the K5 above the 5D II at almost every ISO yet they claim the 5DI can shoot sports at ISO 1815 while the K7 can only shoot at 1162. Leaving aside the fact that this is obviously a calculation (unless you use ISO 162)​
    K-5 high ISO score is 1162. 5DII score is 1815. But a higher score indicates a better performance, not the other way around. If you look at the SNR graph, the K-5 graph is below the graph of the FF cameras (which means it's worse - low SNR means there's less signal noise ratio, i.e. there is more noise). So DxO measures the 5DII as being superior in high ISO performance, just like the other reviewers you mentioned - I see no discrepancy here - their conclusions support each other.
    I am baffled how the lower noise sensor is over 1/2 a stop worse.​
    1162 doesn't indicate lower noise - in this test higher numbers indicate better high ISO performance, so the 5DII number is better. Read the description of the scores here:
    http://dxomark.com/index.php/Learn-more/DxOMark-scores/Sensor-scores/Use-Case-Scores#Sports
    I posted this explanation of the high iso score in the other thread - it's the highest ISO value at which SNR, color depth, and dynamic range are still above a bar picked by DxO as indicating decent IQ. The bar is the same for every camera - the 5DII can be pushed to higher ISO while the K-5 drops below that bar earlier at 1162 ISO. Does it make sense now?
    Also note in the SNR graph that the part where the graphs are similar happens after the SNR dropped under 30db - below the bar, where it doesn't influence this score anymore. I also just noticed now a neat feature in the DxO graph - hover the cursor over the right side, over the green-red bar and you will see an image that simulates the respective SNR, to give you an idea of what noise an SNR number corresponds to. It's not an actual test shot, just a helper to put the SNR numbers into context. They have this for the other graphs too - you may need to hover the cursor over a graph first, to bring the green-red bar.
    On the other hand, the K-5 scores higher in dynamic range and this is the reason it ends up getting a higher aggregated score too - you can argue that the aggregation is meaningless, but they had to make one to come out with a single number - this is why you need to look at individual scores carefully. Incidentally, the higher dynamic range of the K-5 is also supported by the dpreview reviews:
    http://www.dpreview.com/reviews/canoneos5dmarkii/page25.asp
    http://www.dpreview.com/reviews/pentaxk5/page14.asp
    Except the results are not that easy to read - but look at those scales where they compare the DR. The 5DII is in between approximatively 32.5 and 6.5; the K-5 is between something like 33.5 and 5.3, indicating a wider range. So again, no discrepancy.
    Now, take a look again at the graphs for the DR and color sensitivity and hover the mouse over that bar to see how different an image would look for a difference of 1EV, or 1bit of color depth - notice how subtle the changes are there. No wonder you can't see them simply by looking at test shots.
     
  18. Let me just say that it is possible to over-think this stuff, perhaps even possible to way over-think it.
    I recall reading a wonderful post a Luminous Landscape a year or so ago - perhaps even related to one of the earlier DXO test postings - in which the author pointed out that every one of the cameras in the category under consideration (full frame 20+ MP DSLRs) was capable of producing truly outstanding results. Once you "get" that idea, the whole concern about which body rates .1 higher than which other body on whatever scale you happen to come across somewhere becomes much less significant, if not completely insignificant.
    This is kind of like thinking about going on a very expensive vacation to a very wonderful place and finding three that you think would really be outstanding five-star experiences. You know that any one of the three would produce something truly wonderful. Yet... you have heard that the comforters on the beds at one of them tend to be 1mm thicker than at the others... and you sometimes do worry about getting chilled... and you are looking for something, anything to help you decide which of the three to select. So you end up selecting on the basis of some "difference" that is so small as to be completely inconsequential, meanwhile congratulating yourself on your ability to make logical, data-driven decisions.
    There are other far more significant differences among cameras in a given class that have the potential to affect your photography in more significant ways than what the DXO test number is.
    Dan
     
  19. While reading this thread it becomes obvious many posters come at this from their own relatively narrow viewpoint in terms of arguments pro and con regarding the 5D2 and the K-5, and DxOMark testing.
    I'm no exception but I would offer the following:
    To say that any serious landscape photographer should only be shooting FF is pretty much nonsense or to claim that buyers will reject a print because of the hardware used to capture it. I've sold hundreds of images that I've captured on everything from 4x5s to an Olympus C-5050. You go with what works the best for a given situation or you do the best job of image capture with what you have to work with.
    FWIW, I have personally decided that I wanted more than my 5D2 could deliver and I've moved on to a Pentax 645D. At that point I also decided my Rebel backup system should go as well and I purchased a K-5 so that I could use my 645/67 MF lenses with my K-5. Does that mean the 5D2 and Rebel are 'crap' all of a sudden? Of course not but the K-5 does offer a couple of capabilities for some of my shooting needs that are clearly superior to the 5D2.
    The threads on Photo.net seem full of posts that seem full of angst and lack of civility. We should all be out taking pictures.
     
  20. Charles,
    I hope you are not referring to me when you say "To say that any serious landscape photographer should only be shooting FF is pretty much nonsense". My comment specifically related to printing landscape images at 24" x 36". I am sorry but whilst you can print any sensor size to any output size, most serious large print sellers would agree that the 135 format is an absolute minimum for regular 24" x 36" sale quality prints, I am very rarely happy with such large prints from my FF camera.
    Superb landscape images can be shot with much smaller sensors than a FF one, but to pretend you can do it, and print to that size regularly, is, for a MF digital user, disingenuous.
     
  21. Once you "get" that idea, the whole concern about which body rates .1 higher than which other body on whatever scale you happen to come across somewhere becomes much less significant, if not completely insignificant.​
    Except when one rates twice better. Some differences you cannot afford to ignore.
     
  22. Except when one rates twice better. Some differences you cannot afford to ignore.
    No full frame DSLR rates remotely close to "twice better" than the competition. If you think that data support that, you are misreading the data. In addition, you are likely misapplying the data - unless we can also see that photographs are "twice better" when made with the higher rating camera.
    And, Charles Wood, I like your post. It reflects the real world, not Imaginary Forum World. And, to Scott Ferris, my view regarding the use of cropped sensor versus full-frame bodies for 24x36 prints of typical landscape subjects is in line with yours - here I think that full frame is likely the better choice.
    Dan
     
  23. Scott,
    I can't agree with you that my prior post was disingenuous. Over the years I have always attempted to maximize the quality of my images based on my skills and equipment at hand and it has been an ongoing learning process. I have developed my own style largely centered around large mural size southwestern US landscapes. Solutions that work well for me may not be particularly well suited for others.
    I did fail to point out, as others have many times in the past, that it is possible to create critically sharp large prints with small sensor cameras if one has a shooting situation that lends itself to stitching multiple frames. I don't disagree in general with your comments regarding single frame print sizes but the actual size limitation is more often than not based on actual viewing distance. Customers generally are not pixel peepers. I display a number of single frame images taken with 8-10 meg APS-C cameras from several years ago and when a customer asks if it is possible to print larger, the first thing I ask and qualify is their typical viewing distance. I then go on to explain perceived sharpness vs viewing distance. Across a typical room it is usually very difficult to judge whether a 20"x30" print was shot with an APS or FF sensor.
    I do display and sell large prints, some 3'x9' that I originally captured with 617 format film. To create images of those dimensions with digital can be a bit daunting whether shooting multiple frames with APS or FF 135mm sensors. Digital MF makes it a bit easier.
     
  24. Those who bash the DxOMark testing have not, to my knowledge, suggested an alternative.​
    I know a man who tests the vocabulary and literary skills of fence posts by simply throwing a bag of flour at a wall to see what shapes appear. But hey, his findings must be correct because nobody has suggested an alternative.
     
  25. I wonder often about people who remark in these threads. I know some of you print large, but it you don't, it doesn't matter! I doubt half of you responding print large.
    Last weekend I printed a dozen Super-B prints (13x19 inch, full page) at home with my now old Epson R2400. WONDERFUL output even a couple at ISO 1600 and 3200! The satisfaction you get yourself by DIY is pretty high. It's even better with a good glass or two of wine while you work.
    Equipment: EOS 7D with **good** lenses. I wish I had a newer printer that could tackle a 24x36 inch print!
    Ilford Galerie paper: smooth HW matte at 200 gsm (double sided, but I use an ink pen to record details on the reverse side).
    I cannot think of one print in that bunch that would've improved even 1% with a "better camera or lens". They are Super Sharp and pleasing. Don't worry about the labs like DxO. DIY and examine your technique.
    GUESS WHAT? It's 2011 now and Canon, Nikon, Epson and similar have got it down. You can't lose. You simply can't.
     
  26. "I know some of you print large, but it you don't, it doesn't matter!"
    Pretty darn true.
    Dan
     
  27. No full frame DSLR rates remotely close to "twice better" than the competition.​
    I didn't say full frame anywhere in my response. Across all board, there are cameras that are better than others by a significant margin in one area or another. Without the dxomark rating, you wouldn't be able to quantify the difference other than by saying "much better" and then talking about personal experience. The value of those scores is that we have a more objective measure of the differences and we can get a better idea of how much technological progress one generation provides over the previous one (notice I said "can"). What I tend to notice online is that people usually estimate technology improvements as much more significant than the DxO scores show. People often say one camera is two stops better at high ISO when DxO doesn't even show a full stop difference in their respective score. So I like the DxO scores because they cut through the hype that is usually found online.
    You say people shouldn't obsess with scores and I agree, but that doesn't mean that scores should be ignored as irrelevant as your comforter analogy suggests. Anyway, the middle path is the hardest to follow. Such is life.
     
  28. "I didn't say full frame anywhere in my response. Across all board, there are cameras that are better than others by a significant margin in one area or another."
    The OP began the thread asking about a camera for doing landscape work to be printed at 24x36. As the discussion evolved a general notion (which I subscribe to) emerged that this is probably best done using a full frame DSLR (excluding the possibility of larger sensors) from among the current crop of 20+MP bodies.
    We are not considering DXO as a tool to find out if there is a difference between a 8MP cropped sensor camera and a 24MP full frame camera, are we? If that's what you mean by "across the board," well I guess I can't argue that "across the board" their might be 2:1 differences in performance in some areas - hardly need DXO to tell us that.
    Dan
     
  29. Spearhead

    Spearhead Moderator

    Across all board, there are cameras that are better than others by a significant margin in one area or another.​
    Not in a way that changes what the photographer gets.
     
  30. Just pick up a 5DII, and stop worrying about whether the Pentax sensor may or may not have lower noise at high ISO's than the latest Canon crop sensor.
    That misses the point. For landscape photography, the main knock against Canon is that their top cameras' sensors (1Ds Mk. III / 5D Mk. II) blow out highlights substantially before those in the top Nikon (D3x) and Sony (A900) products do. DPReview puts highlight dynamic range at +3.5 EV for the Canon, +3.7 for the Nikon, and +4.2 for the Sony stop, for difference of 0.2 and 0.7 EV, respectively (see http://www.dpreview.com/reviews/nikond3x/page21.asp). DxO Mark puts total dynamic range for the Nikon and Sony at better by 1.79 and 0.45 stops, respectively (http://94.23.12.156/index.php/en/Ca.../0/(brand)/Canon/(brand2)/Nikon/(brand3)/Sony). That strikes me as a much more significant issue than noise differences, at least for landscapes. Argue all you want about testing methods, and about how much of a difference is significant. In some respects there are issues. But loss of highlight detail is maybe the last remaining important area where DSLR's trail negative film--and where some DSLR brands trail others--to a significant degree.
     
  31. That is interesting, I have found the 1Ds MkIII to have plenty of headroom.
    Here is a misfire from a few days ago in LightRoom, obviously the red is blown pixel warnings.
    00Yr1B-367051584.jpg
     
  32. Here it is pulled 4 stops, again with red blown warning on.
    00Yr1D-367053584.jpg
     
  33. To continue on the thread

    I am sur that the Pentax K5 blows my GX680 and velvia 50 away for dynamic range and many other "objective" tests
    but I have not yet found someone who likes large prints made from any of my DSLRs (although I am stuck in the
    world of 1 series bodies and L glass and have not yet upgraded to the miracles of Pentax bodies and optics) to a scan
    of my MF shots. Indeed while I have little experience of using large format the quality of 10x8 negatives takes some
    beating - although I am sure the latest Casio sensor and optical correction software will do better

    Leonardo should have used PowerPoint!
     
  34. I do not give any consideration to DxO because their rankings quite simply do not reflect reality. See this link for an essay regarding their ranking of MF digital backs lower than FF DSLRs. http://www.luminous-landscape.com/essays/eyes-vs-numbers.shtml
    I have also found their dynamic range tests to be laughable. They do not concur with the results of other sites performing standard transmission step wedge tests, nor do they concur with any of my personal tests or experiences. When I looked up the DSLRs I had plenty of experience with on their site I couldn't help but laugh at their claims.
    I prefer sites which perform more traditional tests and provide test and sample images for personal study and review. DP Review and Imaging Resource are two very good sites. The Digital Picture is also quite good for lenses with the caveat that I have seen some bad lens samples among their tests. These sites clearly state their methodology and provide the test images. You can reproduce their tests or simply analyze their results.
    Regarding 24x36" landscape prints: that is within the capability of the latest crop sensors. I would give a slight edge to the best FF sensors at this size if you have lenses that are up to the task. But it's not night and day, and most people wouldn't notice. I mention lenses because it's a false assumption that FF wide angle and ultra wide angle lenses are automatically better here. For example, if you've got a 7D plus Tokina 11-16 f/2.8 up against a 5D mkII plus 17-40L, my money will be on the crop combo for the better 36" print. And yes, I own both of those lenses and actually hold the 17-40L in pretty high regard.
    This is a print size where MF digital (and MF film when printed properly) starts to show its strength but of course that's a very expensive route. Someone mentioned the D700 but I would rather have a 15-18 MP crop body than a 12 MP FF body for landscapes at this print size. When it comes to foliage every pixel counts and the higher resolution crop sensors will simply yield more detail. If you're going to go FF and want 36" prints, stick to the >20 MP bodies.
    And for the record, I do make 24-36" landscape prints using the 18 MP Canon 7D, and I have compared them to 24-36" prints from FF (5D mkII). I have not felt the need to upgrade, though I am curious as to what the next 5D will offer. I will note that at these print sizes you need to fire on all cylinders. Your lenses, technique, RAW conversion, and post processing must be spot on as this is pushing the upper bound of small format digital when it comes to landscapes. Where you can do it a simple 3 frame stitch will take you much farther, well into MF territory.
    So...if you want to do large landscape prints in the Canon system and can afford it, a 5D mkII and the best glass (i.e. 16-35L II; T/S primes). If you can't afford it, any body with Canon's 18 MP crop sensor and the best glass which, in some cases, happens to be cheaper on crop (i.e. Tokina 11-16 f/2.8).
    And of course there's nothing wrong with Nikon, Sony, Pentax. I just wouldn't choose any system based solely on a DxO number.
     
  35. The OP began the thread asking about a camera for doing landscape work to be printed at 24x36. As the discussion evolved a general notion (which I subscribe to) emerged that this is probably best done using a full frame DSLR (excluding the possibility of larger sensors) from among the current crop of 20+MP bodies.​
    Frankly, I lost that point when you went into that analogy about vacations and comforter thickness. But I'm with you now.
    We are not considering DXO as a tool to find out if there is a difference between a 8MP cropped sensor camera and a 24MP full frame camera, are we? If that's what you mean by "across the board," well I guess I can't argue that "across the board" their might be 2:1 differences in performance in some areas - hardly need DXO to tell us that.​
    My impression from your post was that you were totally discarding DxO results, not that you were saying that the difference between FF cameras are negligible. And as it happens, even restricting our discussion to FF cameras, the Nikon D3s seems to have a stop advantage over many other cameras including the 5DII and 1DsIII. 1 stop = twice better performance - I think most users would easily appreciate this.
    In another category, the D3X has one more bit of color depth vs. the 5DII. 1 bit is twice the colors, although I grant you that at that level our eyes are the bottleneck in distinguishing the difference, so maybe this is a minor improvement.
    On dynamic range, I'm not sure what would constitute twice the performance - twice the Ev maybe? Hard to find, but I believe we don't need twice the performance in this area to derive a good deal of benefits. And you can find plenty of samples where differences are around 2Ev between FF cameras, or even between an APS camera like the K-5 and the leading Canon FF cameras. Not sure how 2EV is as negligible as 1mm difference in comforter thickness. In particular it should make a good deal of difference for landscaping photography, all other considerations aside. So why is it even a foregone conclusion that FF cameras are the best for landscape photography?
    Bottom line is - there are plenty of significant differences. Some, like color depth, may only be noticeable by the keenest eyes. Others, like high ISO performance and dynamic range will be more easily appreciated by everyone.
     
  36. 1 stop = twice better performance - I think most users would easily appreciate this. . . . I'm not sure what would constitute twice the performance - twice the Ev maybe?
    I don't agree. First off, 1 EV is one stop. The unit EV is an attempt to generalize exposure away from being affected by only (or primarily) the iris (f-stop) to also depending on the shutter speed etc. So they mean the same thing, as used here.
    But anyway, handling twice as much light before blowing out is not twice the performance, in a meaningful sense. Is it useful? Yes. Are there times when it can mean the difference betweeb getting a good shot and getting one that is not too useful? Yes. Will it matter for most shots? No. Or at least, IMO / IME.
     
  37. To our OP Brent. Since you're a noob to digital photography, your concerns are easy to understand. If you could find your way to afford a MF digital camera, I think you'd still have a substantial learning period before you'd be entirely happy with your results.
    For landscapes you'll likely be shooting at low ISOs, with the best lenses you can afford, on a tripod and using remote release. All those tools were available to you with film, plus you had the huge advantage of shooting 4x5. However, there are new tools available to you in digital photography that you will need to learn. HDR (high dynamic range) photography is one tool that you're likely to use, where you bracket the exposure with multiple images and then combine the images in your processing to achieve dynamic range that might rival your 4x5 film.
    Also, sensors behave differently than film. If you shot slide film, then your objective was to get the exposure "perfect" in the camera. In digital you'll "expose right" when you create your RAW "negative", such that the in-camera jpeg will look a bit over exposed. Exposing to the right of the histogram, without overexposing highlights, will yield greater dynamic range. When you convert the RAW image to your working image, you'll pull the levels down, add contrast, adjust WB, add Vibrance, sharpen, etc. At some point, you'll create your own custom processing templates that you apply to 90% of your prints. This is NOT the same as Photoshop manipulation, but merely part of processing a digital image, much like printing a film negative.
    This brings up another point. As part of the RAW conversion process, many softwares like Lightroom and DxO's Optics Pro, adjust for camera body and lens errors, such as CA, geometric distortion, vignetting, etc. at every focal length (for a zoom) and every aperture! Many tests will show the results of uncorrected images, BUT that's not the way many of us shoot anymore. When you go digital you'll need to select a front-to-back systme that includes not only body and lenses, but processing software.
    Oh, for your astrophotography, digital has huge advantages with the ability to stack large number of images, yielding HUGE dynamic range and detail that's hard to imagine until you see the results. However, once again, the post processing software will play a huge role in the ease of processing and success.
    Oh, btw2, you're talking about large files. You need to make the Win/Mac choice, make sure you have a fast, high capacity processor with lots of memory (6 to 8GB) and a 64-bit OS, in the Win environment.
    All that is pretty daunting when you consider it all at once. I think that you should proceed initially with a FF body and just as much care applied to your lens selection as your applying to the body selection. Whether you go Nikon, Canon, Pentax, etc. make the range of available lenses vs. your expected usage the main criteria, but also realizing that you may step up to MF in the future. I suggest FF to start merely because you'll be in training for a year or so. The forums are more active for the FF and crop format DSLRs and you've got so much to learn.
    In the very beginning, you should consider shooting both film and digital, particularly for critical subjects. Learn about HDR early on and don't be put off by the thousands and thousands of cartoonish HDR shots that you'll see. Used as a tool to increase DR, it's very useful. Still, I predict that your film images will beat your digital images, but the quality will converge over time as you learn the tools of digital imaging.
    Once your digital images rival your film images, then you can consider MF vs. FF. If money were no object, you might skip right to MF, but you've said that it IS an issue, so I'd start with FF. Consider a lightly used camera to hold down costs. Digital bodies depreciate really fast and only stay "current" about 18-months. Of course they continue to work, but there's always a new sensor with better high-ISO performance, more pixels, etc.
     
  38. My impression from your post was that you were totally discarding DxO results, not that you were saying that the difference between FF cameras are negligible.
    I'm largely discarding DXO results, unless the person using them a) fully understands what they do and do not imply, and b) that they correspond in useful and meaningful ways to what we see when we actually use the equipment.
    And, I was indeed saying that the differences between FF cameras are negligible. That was essentially my primary point.
    I'll also suggest that it would be a good idea to step away from the test results and consider about how these things really do and do not play out in those things known as photographs.
    Dan
     
  39. I don't agree. First off, 1 EV is one stop.​
    I agree. I was just saying that 1 ISO stop allowing you to shoot at higher ISO allows one scenario - shooting in low light at higher shutter speed, which can feel like twice the performance. But 1 EV extra may not come into place for most scenes that don't need that extra EV (assuming we always expose correctly, of course - you could use the extra EV for recovering the image from the RAW file, otherwise), so the perception won't necessarily be of getting twice the performance. I think we're really saying the same things.
    I'm largely discarding DXO results, unless the person using them a) fully understands what they do and do not imply, and b) that they correspond in useful and meaningful ways to what we see when we actually use the equipment.​
    This sounds to me like shooting the messenger because you misunderstood the message. Why would you penalize objective results because people don't spend the time to understand them?
    And, I was indeed saying that the differences between FF cameras are negligible. That was essentially my primary point.​
    1 extra ISO stop performance difference would always be useful to me, but everyone has their evaluation criteria. 2 extra EVs would be helpful too.
    I'll also suggest that it would be a good idea to step away from the test results and consider about how these things really do and do not play out in those things known as photographs.​
    Like I mentioned earlier, I did that, and I came to trust these test results. I agree that for a lot of applications, the differences won't matter to the users, but for some they will.
     
  40. Why would you penalize objective results because people don't spend the time to understand them?
    That wasn't my main point, either. I'll make one more attempt to explain this, and then perhaps be done. (I eventually get tired of arguing about things I didn't say.*)
    1. Test results such as those from DXO and others often contain real data and extrapolate certain conclusions from these data. I'm making no judgment of the validity of the underlying data used in DXO reports.
    2. A frame of reference is always needed to understand the significance of data. For example, we could say that product A costs twice as much as product B, but it is important to know what the two products do and that one price is not from 20 years ago and one from today. Particularly when products are ranked in numerical sequences indicating a quality rating, it is important to know the criteria used to establish the ranking. For example: "We tested lenses and lens A ranked #1, lens B ranked #2, etc." means one thing if they tested the weight of the lenses, another thing if they tested spherical distortion v. price point, and yet another if they tested the AF system.
    3. Even when real and measurable differences can be quantified among tested products, questions remain about the significance of such measurable differences. Let's say that one lens can test at X lp/mm and another can test at X+1 lp/mm resolution. Yes, one lens technically has "higher resolution," but this would be completely meaningless in actual photographs. If you make prints with identical cameras using the two lenses and put 40 up in a gallery, no one would be able to sort them by lens.
    Bottom line: Knowing about the technical performance characteristics of gear is not unimportant. Obsessing about test results and extrapolating conclusions that don't hold up in real photography is not a very effective approach.
    Bye.
    Dan
    *This is an old and familiar argumentative strategy that is often employed by people who are less concerned with understanding the fundamental issues behind the question and perhaps more concerned with either the pleasure of arguing or who recognize that one way to "win" is to deflect the discussion so effectively and continuously that no response will end it. By taking what the other person said and stating that the person said something that they did not say but which is typically pretty foolish-sounding, the person employing the strategy often ends up arguing not the other person's point, but instead arguing against a phantom that they invented.
     
  41. And for the record, I do make 24-36" landscape prints using the 18 MP Canon 7D, and I have compared them to 24-36" prints from FF (5D mkII). I have not felt the need to upgrade, though I am curious as to what the next 5D will offer.
    Thanks for the data points Daniel. JUST what I wanted to read as I am queing up the 7D for some large prints like that.
    I will note that at these print sizes you need to fire on all cylinders. Your lenses, technique, RAW conversion, and post processing must be spot on as this is pushing the upper bound of small format digital when it comes to landscapes. Where you can do it a simple 3 frame stitch will take you much farther, well into MF territory.
    I don't have the patience to stitch -- I do, but maybe 1-2 a year? They are always far from perfect.
    Technique and glass, and of course the more MPs the merrier, are what you need to print beautifully large.
     
  42. *This is an old and familiar argumentative strategy that is often employed by people who are less concerned with understanding the fundamental issues behind the question and perhaps more concerned with either the pleasure of arguing or who recognize that one way to "win" is to deflect the discussion so effectively and continuously that no response will end it. By taking what the other person said and stating that the person said something that they did not say but which is typically pretty foolish-sounding, the person employing the strategy often ends up arguing not the other person's point, but instead arguing against a phantom that they invented.​
    FYI: I believe you are trying to describe a strawman argument.
     

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