Quality 'shifts' on Lenses + 2 other Q's.

Discussion in 'Canon EOS' started by sonny_jet, Sep 20, 2005.

  1. Hi,

    I have been taking 'snaps' on my 35mm canon AE1 manual camera for a
    long time now. Recently I dug DEEP into my student loan and have
    purchased a Canon 20D d-SLR plus a few lenses (EF-S 10-22, EF-S 17-85
    IS, 70-200 F2.8 L IS and a 100mm f2.8 macro), and a 1.4x TC. I am
    definately not a pro - far from it. I just enjoy taking pictures of
    anything and everything. From macro to landscapes and more recently
    (thanks to digital) portraits. It is great checking how a picture
    came out of a persons face to make sure they didn't squint their eyes
    etc. Go digital!

    I have been reading people's comments on this site for about a month
    now and have learned many, many new things. However, the more new
    things I read about and learn, the more questions I seem to have. I
    could type out a whole list of questions but have decided to post
    just a few. It will be great if you can help with these:

    1. I have often seen comments from people on this site who say that a
    lens will perform better on a crop framed camera (i.e. my 20D)
    because the crop framed camera uses the centre of the lens and
    therefore the pictures taken will not show up problems (primarily
    lack of sharpness) that often occur towards the edge of the lens. How
    true is this? For example if I shot with a 24-70 f2.8 L on my 20D at
    50mm(31.25mm on my 20D) and 50mm on a FF camera (1dsmk2eos 5D) -
    would the picture be BETTER (in terms of sharpness etc.) on my 20D ?
    (I hope that question makes sense and isn't a silly question)

    2. Before I ask the next question, I would just like to say that I
    don't want to turn this into a '24-70 L vs 24-105 L' question. As I
    have just spent the last hour reading opinions on the very issue.

    I often read people with much more knowledge about photography than
    me, making statements such as "the new 24-105 f4 L is much better
    optically at wide angles but poorer at the telephoto end" or vice
    versa. What I would like to know is, L lenses (for example 24-70 f2.8
    or the new 24-105 f4) at their WORST (i.e wide angle + telephoto end)
    will they still be better than my current 17-85 EF-S IS?. If the
    answer is yes, then I can't wait to get my hands on one of them!
    Because my 17-85 is great but edge to edge sharpness is definately
    not amazing and so moving to a 24-70 or 24-105 would be fantastic. By
    the way, just to get my 2 pence worth in: I probably would go for the
    24-105 F4 L because I do not require (as far as I know) fast shutter
    speeds indoor and the IS can counter the faster f2.8 of the 24-70
    with its IS for indoor shots. I am assuming the quality DIFFERENCE
    between these 2 lenses is not going to be MAJOR - in which case - I
    am probably going to be happy with either.

    3. I have just been shooting in JPEGS but will hopefully start using
    RAW and look to edit my pictures with the software that came with my
    20D or perhaps PS. I also need to get a flashgun very soon.

    Do any of you helpful people know of any resources on the net that
    can help with me getting use to my 580EX or flashguns in general. I
    did the usual search on google but there were just too many hits. I
    need help with everything but flashguns is an area where I really
    don't know anything! I thought 'rear sync' was referring to the basin
    in the bathroom at the back of my student accomodation.

    Thank you very, very much.
  2. Hi, Sonny

    1. If you are looking to buy an L lens, like the EF24-70 f/2.8L, then I would not pay too
    much attention to this issue of "quality shifts". You are getting a great lens. Period! IMHO
    it would be difficult to do a straight comparison of the image from the 20D with the image
    from the 1Ds MkII or the 5D because the image sizes would be different. How would you
    take this into account? If you are talking about sharpness, you would need to apply
    sharpening to your image in any case (although the degree of sharpening might differ) so
    that criterion doesn't really help you.

    If you want to compare the Canon L lens with a cheaper and slower Tokina zoom then that
    is a different matter, but the important thing is that you are getting a great lens if you go
    for the Canon.

    2. Probably. As I said, the 24-70 is great. I expect (from what I've read) that the new
    24-105 will also be great. Choose the lens that is best for you. If you want/need IS go for
    the latter. If you want f/2.8 go for the former. IS is useful, but doesn't help with subject
    movement. When you say you are going to take indoor shots, is it likely that subject
    movement will be an issue?

    3. The Canon EOS flash FAQ is the best place to learn about the Canon flash system.

  3. Wow, there is lots of info at that site. THANKS VERY MUCH.
  4. Hi Sonny -

    First of all, the camera and lenses you bought are all first rate. You should go out and do a few thousand shots with those instead of worrying about what lens to get next! I speak from experience here - I'm a gadget hound myself and I bought many lenses in the first few months of shooting, many of which I hardly use.

    That said - here is what I know about the topics you asked about:

    1. Don't know.

    2. Again, don't worry about getting another lens! I have the 24-105 but not the 24-70 so I can't compare but I like the IS on the 24-105.

    3. This is where you can still make an investment if you want to spend some more money. Get Photoshop CS2 and a couple books on how to use it - then spend some hours working with the program. Start shoooting in Raw and using Adobe Raw to convert your photos to JPEG. Photoshop can make a big difference in the prints you ultimately produce. You can't make a mediocre photo into a great photo but sometimes you can rescue a really good photo with a fatal flaw using a little (or a lot of) editing.

    Also, a good flash like the 580EX is a nice addition. There is a lot of Canon flash info on http://photonotes.org/articles/eos-flash/ Read the whole thing, and read some of the other articles on there as well: http://photonotes.org/articles/

    There are tons of good books on photography out there but Understanding Exposure by Bryan Peterson is terrific and will give you lots of ideas.

    You may also want to invest in more hard drive space and a CD/DVD burner for image backups. Also, an image cataloging application like iMatch or ACDSee will be useful in a very short time.

    I don't mean to give you a hard time but really - don't get any more lenses. There are a lot of other aspects to this hobby that you can learn first. You've got a great set of lenses for a pro, much less for a hobbyist!

    Maybe it would help if you make yourself some assignments like you do in school? Both FredMiranda.com and dpchallenge.com have weekly assignments that you can participate in and submit photos to. Even if you don't submit your efforts at first try doing the assignments and you'll learn a lot in a very short time. Good luck!

    - Mary
  5. 1. - well it is true, to some extent, that most lenses perform better in the centre than their edges. Following that, a pitcure which is cropped may hide some of the lens "deficiencies". However, with better glass the difference is usually less visible. But, generally speaking YES, lenses have a better performance in the center therefore, on a 1.6 crop camera you get the better part of the lens ;)

    2. - I have the 24-70L and I have found it to be pretty much on par with my 50s and much better than my, 28-135 IS (now sold). Your lense, the 17-85 IS is very similar in performance to the older 28-135 therefore the jump in quality should be about the same.

    3. - for flashes I use three 550EXs with an ST-E2 and am very happy with their performance. Personally, I see little or no reason to get the new line (580/430) so, I didn't.
  6. THANK YOU Mary for your honesty; Nigel for your technical know how
    and Giampi for making me a little happier with your response to Q1, plus anyone else who offers their excellent advice/opinion.

    The reason I REALLY, REALLY would like a 24-70 L or 24-105 L is because I would then be content and would not be after any more gear for the next 5 years, atleast (Or so I think!). Plus, the 40-100mm focal range is really important for me and I guess it is for alot of other people. And so, why not have the best glass (i.e L glass) in that range? The 24-105 L will be a 38-168mm, which is perfect.

    To be honest, I haven't even got round to using the 70-200 f2.8 L IS or the 10-22 EF-S, YET. I managed to afford my kit by eating rice for a month and to limit my university partying to 1 night a week, as well as extra overtime at work. And if I keep this up for another month then I will be able to get the 24-105 L that I need (want!). THe other thing I forgot to mention is that, I have an old but MINT condition 35mm F100 + manual FE2 that are collecting dust. So, I was hoping to sell them as well as my 17-85 IS and go for the new 24-105 L. Hopefully, the difference between the money I get for them and the cost of a 24-105 L is very little.


    ps. Nigel, your photos are great! Especially the India/Vietnam ones. For the black and white close up of the vietnamese gentleman (with wrinkles on his face), which lens did you use? I am guessing you altered the picture using software afterwards? Just how much alteration was needed? (time wise?)
  7. Hello again Nigel,

    I forgot to answer your question. Indoor movement is not a problem for me. Infact, like getting movement in the pictures! I recently took pictures at at home for my dad's 50th birthday party (using the pop up flash) The motion blur of him cutting the cake + dancing (as well as other family members' characteristic movements) really 'made' the pictures for me and I was pleased with them. I can't see myself needing f2.8 for indoor shots in the forseeable future. Infact, I don't really enjoy taking pictures indoors very much, especially at night. I can't stand using flashes and the 'artifical' look they give to pictures - Though, I think that's my fault for not learning how to use 'fill flash' effectively, which I must learn to do soon. OR perhaps I can save up for a 35mm f1.4 L (56mm on 20D) ;) Aaaaaah if only..
  8. Sonny,

    Actually, I feel that Mary has provided you with the most useful response to your
    questions. You already have great lenses, and getting some new L glass (whether the
    24-70 or the 24-105) is not going to make you a better photographer. Another thing to
    bear in mind is how you will carry all of this kit. I bought the EF70-200 f/2.8L IS when it
    first came out, but I have used it only a handful of times. It is just too big and heavy to
    take with me on my travels, and I don't like the idea of sticking that great big white canon
    (small 'c') in someone's face. I'm thinking of selling it and buying the EF200 f/2.8L prime
    (funny, because I used to have that lens but sold it to buy the zoom!). Of course, I am as
    much an equipment junky as the next person on this site, so I can't lecture you about not
    buying new kit. Go ahead and do what you feel is right! I'm sure you will make the right

    Thanks for your comments on my portfolio BTW. I'm going to be adding more images
    soon, as I'm slowly scanning all my slides on my new Minolta Scan Elite 5400 II. The B&W
    photo you asked about was taken with the EF100mm f/2.8 macro lens (my favourite lens
    for portraits), which I see you also own. It was shot on Agfa Scala ISO 200 B&W
    transparency film (so it was in black and white to start with). The only thing I did in
    Photoshop was a very minor Levels and Curves adjustment (I prefer to do this in PS rather
    than in the scanner software) to bring out the data captured by the scanner and then apply
    some sharpening using the Photokit Sharpener plug-in. All in all, this probably took about
    ten minutes to do. Mary is also right BTW about the value of owning PS and of learning
    how to use it properly. This takes a lot of time, but is well worth it. The digital darkroom
    forum on this site is a great resource for PS.

    Now to come back to your 24-70 vs 24-105 dilemma, it seems that you are pretty much
    set on the latter, as IS will be more useful to you than f/2.8 (subject movement is not an
    issue for you). Another thing to bear in mind is that the f/4 lens will no doubt be smaller
    and lighter than the f/2.8 one. But, as you indicated in your original post, you are going to
    be happy with either of these.

    Good luck with your decision and your photography,


    PS Giampi is absolutely correct that most lenses will perform better in their centres. My
    point was that we would be comparing different images sizes, and so the comparison
    wouldn't be a fair one. Otherwise, more people would be selling their LF and MF gear and
    buying APS cameras.
  9. I think you already have enough lenses to keep you busy for many years to come. Just learn to use them and develop your own style. Check the Luminous Landscpae website for a series of instalments on photography by a great photographer, Alan Briot.
  10. Canon publish a lot of MTF data and much but not all can be told about a lens from this. Issues
    1) Canon data is computer simulation so lens build quality and complexity losses are not included. Probably a usefla

    relative guide though.
    2) Will not tell you anything about flare, distortion etc. Does give a good indication of contrast and detail and to

    some extent bokeh.
    3) Canon publish a book with these in the back for most lenses and telecnverter combination (Lens Work III). A lot

    of the data is available from the USA and Japan webs but is sometimes contradictory so I recommend the book except

    for the new lenses EF-S and the new 24-105.
    USA web: consumer.usa.canon.com/ir/controller?act=ProductCatIndexAct&fcategoryid=111
    Japan Web: http://cweb.canon.jp/camera/ef/catalog/category

    I have looked into the comparision between lots of lenses MTF data to guide my lens selection. This is on my web

    pages at http://www.zen20934.zen.co.uk/photography/lensselection.htm and

  11. Hi Sonny, I guess I have a comment on your first question, regarding lens performance on "crop-framed" cameras. I read all the responses here in a bit of a hurry, but missed seeing any comments on the magnification factor when it comes time to print your shots. Lenses most certainly do exhibit better resolution and contrast as you get closer to the centre of the image circle. However, remember that your "crop-framed" dSLR (eg. 20D) has a smaller sensor, and so any print from the sensor will entail a greater magnification than an equivalent print from a full-frame dSLR using a different focal length lens. Greater magnification means the print will be more likely to reveal optical deficiencies that might otherwise not be revealed at lower magnification. So, the thing is, yes I think lens performance is better near the centre of the image circle, but IS IT BETTER ENOUGH to "beat" the extra magnification you need for your print? That's the question, and I haven't done the numbers on this.
  12. Hi David,

    Thanks for making your comment. I never thought about that. Very good point. I, of course, hope that my 20D utilising the centre of the lens overcomes (even if only slightly) the defficiencies shown by the larger magnification factor that you mentioned. I have no idea if this is true and am not too worried about it. Thanks once again for that interesting point.

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