jon_savage

Assuming you mean a single shot to crop in you need a very long lens and a sensor with lots of small pixels. I've managed tiny cropped snapshots with a Nikon D7100 and a Sigma 150-600 at 600mm and f6.3. The subjects are in bright sunlight so you can try starting at settings around 1/00th and iso 200 and go from there. No need for very high iso's or very long exposures. Here's a couple of old threads about my related attempts on the ISS and Jupiter that have setting information.

Astro Photo Op

Photo of Tim Peake! (on International Space Station)

Shoot in raw and don't be afraid to tweak it a lot to get something (or probably I just got my exposures wrong!). I took lots of shots at various settings and a few worked out OK so do experiment. I have done Mars, Saturn and Venus but I don't recall the settings. My portfolio here has Saturn in it to give you an idea of what you might expect.

There's nothing to lose having a go. :)

I've tried a few times getting images of the odd planet with a DSLR and long lens. I really can't recommend enough at trying to get a view of the planets (well, Jupiter and Saturn are the ones that impress) from your back garden or even just getting a look through a telescope. The first time you see them for real is quite something.

Then tweaked within an inch of its life in Light Room until I got something recognisable :

Obviously 100% views.

I think I just supported the camera on a tripod and followed the bright spot buy hand. I have a motorised tracking mount but I don't recall using it for this but I might have done.

So hopefully this can give you an idea what settings to try and what to expect. Next try Saturn and then the ISS.

But be warned it could be the slippery slope to astrophotography.

Jon

Shun, it’s not my Sigma!

I don't mind what the op buys but I obviously do care that he gets exposed to many options and understands their compromises. Otherwise I guess I wouldn’t contribute to the discussion to hopefully help him make the right choice for his situation.

Dieter brought up the suggestion “if I wanted a constant fast aperture and superb performance, then I would get the Sigma 18-35/1.8 and Sigma 50-100/1.8” and made the interesting comparison seeing them as a full set of standard primes without the cost and changes.

Mike agreed with the suggestion (“spot on”) and suggested cropping may be an acceptable way to get the gaps filled.

You said DX couldn’t get the best image quality and suggested it was too heavy and discussed primes on a different system. I was trying to add some factual data to various opinions to put all the pros and cons in some context. Only the op knows what his budget, usage and acceptable compromises are and if they are totally unacceptable to him or not.

My choice was a £200 used Tamron 17-50 2.8 non VR for my D7100. Very nearly bought the Sigma but in the end decided to save and upgrade to FX.

Gary,

“About FX vs DX in low light. It is the capture area of the pixel.

The theory is for a similar sensor capacity, say 24MP, the FX pixel is larger than the DX pixel, thus capturing more light.”

That theory is really only applicable if you use the sensor like a solar panel in a field under the sky. Like a camera body with the lens removed.

With a camera system there is also a lens to consider. The lens must focus the available light from the field of view onto an image circle the size of the sensor or you obviously can’t get an image! You can choose to spread that amount of light either thinly (dimmer) over a larger area or thicker (brighter) over a smaller area.

So if camera systems have different sensor sizes but have the same size* lens and have the same field of view they will in theory perform the same in every aspect when you view the final image. Any differences we see will be in things like manufacturing and technology limitations and not due to the different sensor sizes.

A sensor can only collect the light it’s given. What you are taking a picture of doesn’t get any brighter because the sensor the other side of the lens changes size, the amount of light passing through the lens stays the same.

Jon

* same lens size as in the aperture area that lets the light in

Shun,

“I am afraid that is a totally unfair comparison” - I disagree. For someone looking at standard DX zoom options the comparison was intended as useful information to consider in the cost, performance, size and weight trade-offs they might be willing to take. It was especially a fair comparison as it was highlighting all the differences.

The comparison is:

Two lens DX system covering, “27-150”/”2.7” with a 53-75 gap £2,300 (less if as the op already has a DX body)

Two lens FX system covering “24-200” “2.8” with no gap and maybe VR for £3,500-£4,500.

“Low light performance”: exactly the same. Weight and size: in the same ballpark.

You added a third/forth comparison (that may or may not be considered a totally fair comparison to a zoom kit :)):

Multi 1.8 prime lens FX system, lens examples could be some of: 24mm £650, 35mm £435, 50mm £125, 85mm £425, 135mm f2 £1190 180mm f2.8 £750

Multi 1.4 prime lens FX system, lenses like 24mm £1,800, 35mm £1,600, 50mm £390, 58mm £1,500 85mm £1,500, 200mm f2 £5,000,

That “very useful focal length range” of 53-75 is hard to fill with a fast prime. Obviously, these FX prime systems have the best light gathering capabilities (biggest diameter glass) but at cost, weight and the lens swapping and missing focal range inconveniences.

The point I was picking on was you stating that DX is not going to give you the best low light performance. If you are talking zoom DX then the circumstances described can give DX the best (if best = FX) image quality but only in the above focal ranges. The DX price you pay to equal the FX zoom low light performance is it's only in the limited zoom ranges and also, if it’s important to you, it saves you money.

You pays yer money and you takes yer choice. I’m just describing one of the many choices.

Shun,

OK, a controversial approach reference the statement “DX is not going to give you the best high ISO results” :)

If you are looking for fast, cost effective standard range zooms I don’t think that statement applies. I’m assuming by high ISO results you are talking about the best noise and dynamic range possible in an image for the given available light.

D7500, Sigma 18-35 and 50-100 at 1.8 for £2,300

For an FX equivalent of 27-53 and 75-150 at 2.7 I guess you’ll need something like: D750, 24-70 and 70-200 at 2.8. This kit is £3,500-£4,500 depending on lens brand.

Across the shared ranges there is no sensor advantage as you are a stop slower on FX (so higher ISO and so increased noise and lower DR). The physics says the photos are exactly the same.

System weight and maybe size are similar, again depends on FX lens brands. So if DX Sigmas zooms are too big and heavy I don’t think going FX zooms will change things for either size or quality.

For all that extra money spent you do get the 53-75 range filled (is this range that popular “you will be changing lenses very often”?) and the longer 150-200 range and probably VR.

Maybe worth the £1,000-£2,000+ (+50%-100%) extra cost? I’ve certainly been drifting to this set up over the years.

Fast primes on FX will get you that extra light but at a significant cost, weight, lack of DoF and lens changing compromise. What 1.4 or 1.8 prime can you use for the “pretty big gap” between 35-50 DX (53-75 FX)? The 58mm 1.4 at £1,500 fits nicely in the middle.

But if you just want top class standard range zoom photography a DX system is difficult to beat for the price and performance. If you are OK to stop there fine, but in the future if you want big diameter fast glass and the benefits that can bring you will need to ditch DX as FX is where they are.

Just food for thought,

Jon

<p>Shun,<br>

I will check it out more carefully when I get the chance. It is without doubt impressively sharp in the main area of the lens. But the corners are distorted and soft at the wider end. But having looked through many of my photos with my old DX wide angles (the Nikon 10-24 on a D7100 and before that the Tamron 10-24 on a D300s) I noticed I rarely had much of interest in the corners in what I took so it's hard to really compare.</p>

<p>Simple distortion I can live with but too much blur/softness beyong the extreme corners might be an issue for me, that was why I went from the Tamron to the Nikon before. I guess if it appears no better than the Nikon 10-24 on my D7100 I'll change it.</p>

<p>Shun, I looked throuigh the images I took and there were only a couple at 16mm and f4. And only one with useful image in the corners. So appologies in advance for the dull subject but it may give some indication of the corner performance - see attached straight from camera jpeg.</p>

<p>Having looked extra close in the corners there is some distortion right in the very corner when wide open (possibly top right the worst). But it's very sharp in the majority of the frame.</p>

<p>Thanks for the responses. I guess one doesn't stand out as a clear winner. So in the end I went for the Nikon 16-35 F4 VR. Not too big (but big enough) and takes my existing filters. I tred it carefully in the shop and the sample appeared very good all round so I took a deep breath and parted with a few more pounds than I planned!</p>

<p>It actually stopped raining and the sky had the odd hole in the clouds today so I had a chance to take it outside. Nothing interesting to see but all looks OK.</p><div></div>

<p>I’ve recently bought a used D800 and now have the pleasure of choosing a wide angle zoom for it. Up till now I used a D7100 and the Nikon 10-24.</p>

<p>I could stretch to £800. First I thought the Nikon 16-35mm f/4G ED VR (£650-700 used but saving doesn’t look good against £800 new). But reviews seem quite mixed on the optical quality ranging from the best to average and I'm hessitating.</p>

<p>I just wondered what the Nikon forum thought. There's the new Tamron (£800) and the Tokina (£670) 2.8's. The downside would be the extra for a filter kit. Or maybe the new 18-35mm f/3.5-4.5G at £500. I see that gets very good reviews.</p>

<p>2.8 is only needed for astrophotography landscape so that might be addressed with a Samyang 14/2.8 to compliment a more practical and economical zoom, especially if one only goes to 18mm.</p>

<p>Fixed aperture is not important and size/weight possibly less important (unless your comments suggest I should be concerned!) than optical quality and budget.</p>

<p>Thanks for your help</p>

<p>Thanks for the responses.</p>

<p>I really wanted to plan a long exposure trail of it but the timing (for me to get to a suitable location in early evening) and definitely the weather here isn’t helping. Just popping outside the house trying this telephoto shot was much more convenient!</p>

<p>I think next time I might try the 1.3x crop mode jpeg at highest fps (7?) and stack some to see if I can get more information out of the images. If you get the exposure right you might not need the extra dynamic range in RAW.</p>

<p>On other nights I’ve had sharper single shot images of the moon (on the same set up) than this one so maybe the sky wasn’t as clear as it could be or the focus as good.</p>

<p>It didn’t pass close to the moon. I’m not sure when or if ever it crosses the moon from viewing in the UK but to get a better sense of scale I cropped two together. I printed it up at 36x24 cm and it came out much better than I expected as on screen it looks a bit soft and grainy.</p>

<p>If you are interested I found 1/1250^th sec and ISO 400-800 best at f6.3. Upping the ISO appeared worse as the grain started to impact on your 30 pixels. The auto colour balanced looked fine.</p>

<p> I didn’t see Tim wave but I guess he’s busy</p><div></div>

<p>Hi all, thought you might be interested in a shot of Tim Peake - OK, might be a slight exaggeration! (for non-UK based people he’s the first International Space Station visitor we’ve just sent so there’s currently quite a bit of media interest in him over here).</p>

<p>The ISS has spent that last couple of weeks passing the UK early evening and so making good opportunities to photograph. But the weather has not been good. Last Monday when I got home from work for once it was clear so I dashed out to watch it pass.</p>

<p>I had a D7100 and a Sigma 150-600. I focused on the moon manually through the eyepiece as live view was too wobbly and not that clear to see. I also set the exposure on the moon. Then waited and as predicted it came into view and passed quickly. In the couple of minutes it was in view I took a few images at different ISO and shutter speeds.</p>

<p>To my surprise you could recognise the ISS. It was small in the picture, probably not even 30 pixels across. In the sequence you can see it is rotating and as it rotated it picked the light off the sun differently and some shots looked clearer than others. I guess the atmosphere also plays a significant part in clarity.</p>

<p>Anyway, following are some images….</p><div></div>

<p>I thought these links might be of interest to anyone considering a super telephoto zoom. The first talks about the usefulness of a wide zoom range on safari so it’s applicable to all and the other two are just specific to a Sigma with one about it with its dedicated teleconverter.</p>

<p>I agonised over getting one and in the end I got the Sigma Sport a while back. One reason was because the Nikon 80-400 and new 300f4 (to use with a TC) just felt too expensive in the UK. The other was that I am used to 400mm on DX and when I go to FX I’d miss the reach.</p>

<p>I could imagine I would have stuck with Nikon if it had been around at the time as I would have been hessitant to spend that much on a non Nikon lens. But having got the Sigma and used it I appreciate the build quality so I’ve no regrets. In fact I think I could happily try any of their other Sport or Art range lenses based on my experiance of this one and it's USB dock.</p>

<p>I don’t get how the 200-500 it’s so reasonably priced compared to Nikons other new lenses. I guess that Nikon gold ring uses some expensive paint!</p>

<p>http://www.weblogtheworld.com/countries/africa-africa/shooting-wildlife-with-the-sigma-150-600-mm-f5-6-3-dg-os-hsm-sports-lens/</p>

<p>http://dustinabbott.net/2015/05/sigma-150-600mm-f5-6-3-dg-os-hsm-sport-review/</p>

<p>http://georghofmeyr.com/blog/sigma-tc1401-teleconverter-review/</p>

<p>Andrew, I was really only pointing out that larger format doesn't appear to fix the diffraction problems.</p>

<p>I agree that for the shallowest DOF large format may be easier but obviously there are plenty of other considerations when choosing a system especially if going to the extremes of the focal lengths and apertures on a system (size, weight, cost, build quality, plus the modern additions like auto focus systems, VR etc).</p>

<p>I don't know much about large format but it looks like 150mm large format lenses are often f5.6 (so a 50/1.4 in FX?) and a 2.8 one not so common. The only one I came across (not that I looked hard!) was a 150mm Xenotar f2.8, "It weighs seven times as much as the Fujinon-W (f5.6), and if you work with it on your camera you get the feeling that you are budging a spacecraft through a swamp"!</p>

<p>I guess there is always a compromise needed somewhere depending on your own priorities.</p>

<p>Shun,<br>

<br />“If you indeed need more pixels, you cannot keep squeezing them into 24x36mm. That is why you need larger format so that you can once again use f8, f11 without diffraction problems”<br>

<br />If you are having the following scenario:<br>

<br />Someone wants f8 on 50MP FX camera but doesn’t like the amount of diffraction softening at pixel level (because f8 airy disc is 10.7 microns and the pixel size is 4.2).<br>

<br />Are you proposing they should switch to a larger format for larger pixels so they can take their photo at f8 and reduce the f8 diffraction impact as pixel size is bigger (for example MF 54mm x 40mm pixel size would be of 6.6 microns for 50MP)?<br>

<br />But this f8 on a larger format has less depth of field (assuming the same field of view in the final photo) so more out of focus blur in your final photo.<br>

<br />So you stop down to get your DoF back. You would need f12.3 on the medium format example. That gives you an airy disc of 16.6 vs pixel size of 6.6, that’s the same ratio as airy disc of 10.7 vs pixel size of 4.2.<br>

<br />If you want the same final photo it looks like you have gained nothing in terms of the diffraction softening artefact. So I’m not sure going to a larger format will get you round the diffraction problem</p><div></div>

<p>Even the link I posted earlier stated “We just couldn't achieve the same sort of dramatically shallow depth-of-field with a 35mm camera” and “that advantage holds true for this new Pentax 645Z. Its draw for the creative photographer isn't so much that it has 54 million pixels with a pitch of 5.3 microns, but that its 43.8x32.8mm sensor can deliver a crisp full length portrait against a creamy background at an aberration-free f/5.6 and a distance of 15 feet. With a standard 55mm lens”</p>

<p>If creamy background refers to this dramatically shallow depth-of-field I think you can get the same Dof as his 55mm/5.6 with a 44mm/4.5 FX or even a 30mm/2.9 on the little DX. While the quality of his £1000 glass and lens design will impact the aberrations I can’t see for example a Sigma 30/1.4 Art prime stopped down being that bad. It would be interesting to see a proper comparison though...</p>

<p>Even Luminous Landscapes refer to “the fact that it can shoot extremely shallow DOF” in a 645z review as an advantage and Amateur Photographer “The shallow depth of field that is afforded by the larger sensor” relative to 35mm/full frame. But with the availability of fast full frame lenses I’m not sure that statement is as unique to this digital medium format (44x33) they test as they think it is.</p>

<p>This guy lost me completely:<br>

gizmodo.com/why-medium-format-is-so-gorgeous-its-about-more-than-r-160193827</p>

<p>“The key point as a result of that difference [MF vs FX equivalent] is that even though the field of view is wider, the geometry, or "look," of the 50mm focal length remains. You don't get the exaggerated perspective that wide angle lenses usually produce on 35mm cameras. In that regard, medium format mimics how your eyes actually see the world, at least more so than the smaller 35mm size.”</p>

<p>I thought if you choose the focal lengths correctly to take into consideration the crop factors the perspectives are the same.</p>

<p>Some good new though, the high megapixel count doesn’t appear to be an issue:<br>

http://guyaubertin.com/review-pentax-645z-from-a-landscape-photographer.htm<br>

“I don't find diffraction a problem and am happy to use F16 if needed”<br>

With a pixel size of ~5.4microns at F16 the diffusion airy disc is ~22 microns. That’s 4 times the size of the pixel. I guess that’s only an issue if you print large enough to see the pixel level detail. But either way the lack of an issue would also apply to the high MP FX sensors as they wouldn’t have to stop down as far as F16 to get the same increased DOF.</p>

<p>If you are interested I found one informative review of 44x33 vs 36x24 format that came with equivalent image samples and lens options comparisons (40MP 645D vs a D36MP 800). Their conclusion:<br>

“Both cameras produce images of outstanding quality and the for all practical purposes the images are identical in resolution, contrast and color rendition in the ISO range 100 – 400”<br>

And that was from a Pentax website so I assume it’s not biased in favour of the Nikon:<br>

http://www.pentaxforums.com/reviews/nikon-d800e-vs-pentax-645d/image-quality-field-tests.html</p>

<p>I don’t know what the IQ different between them really is having never tested them side by side but this aberration-free with dramatically shallow depth-of-field aspect might be exaggerated a bit but then some people will pay a lot for small improvements. Anyway, I’ve digressed form the point of the thread (sharing the maths) and I’m arriving late reading up on MF and it looks like this has all been discussed before:<br>

http://www.photo.net/nikon-camera-forum/00cWTH?start=30 Is the Pentax 645Z a game changer for Nikon?</p>

<p>I’m still interested in FX for the opportunity of less DoF and therefore the low light and artistic opportunities it opens up but maybe not just yet as the price of a body and a couple of lenses that would show a noticeable difference to my current DX set up add up to more than I would want to spend in one go (I'm saving). I think FX is possibly the best compromise for me as a system in the long run (size, cost, lens availability, DoF opportunities, etc.).</p>

<p>As for ever getting medium format I think I’ll just take pictures at f1.8 with a Sigma 18-35 Art on my old DX (that’s only a 34-70/f3.4 on the 44x33), crop them to 3:2 or even square and save a few quid. As long as I don’t print extremely large no one will ever know :-)</p>

<p>Joe, it’s interesting you say that. I’d not paid much attention to “medium format” having never used it hence my confusing label of Pentax 645 not realising it meant 56x42 to most people. But based on this thread I Googled a bit. It was surprising what kind of information the top hits brought up.<br>

Shallow depth of field appears to come up a lot with MF users. But they do come out with some confusing comparisons. This guy reviews a 44 x 33 MF sensor:<br>

http://zackarias.com/for-photographers/gear-gadgets/why-i-moved-to-medium-format-phase-one-iq140-review/<br>

Half way down his review he has a man sitting up at a table with back focus on the eyes, “This was shot with the 55mm 2.8 lens at f3.2. The 55mm is “about” a 35mm focal length in terms of full frame DSLRs. So it’s a bit on the wide angle side of things. Notice how I got the far eye in focus but the near eye is going soft. I’m at a decent distance from Dan with a wide lens. A DSLR with this set up at f3.2 would have held both eyes.” I think he’s mixed up his formats and talking about a larger film MF size vs 35mm – see table in image below. I'm not sure the difference is that much (say 17 v 21 cm around where he focused??).</p>

<div></div>

<p>Antonio, thanks for the clarification. It looks like you used the sensor areas for the crop factor calculation and I used the diagonals.</p>

<p>Also just to clarfiy I'm not saying the 645z to FF difference is "trivial", but I did say it was too exspensive for me :-)</p>

<p>Rodeo Joe, I don’t think there is an error, I think you have assumed a different sensor size than I used for the column headed “Pentax 645”. This was for the Pentax 645 digital cameras (645D and 645Z with a sensor size of 44x33). So maybe I needed a clearer heading so it’s not read as “Medium Format”. For example this Pentax 645:</p>

<p>http://www.techradar.com/news/photography-video-capture/cameras/does-anyone-really-need-a-digital-medium-format-camera--1246587<br>

(in a techradar article on "digital medium format")</p>

<p>I don’t think you must use the diagonal but it’s a good one to use and if you believe Wikipedia the most common one:</p>

<p>“In digital photography, a crop factor is related to the ratio of the dimensions of a camera's imaging area compared to a reference format; most often, this term is applied to digital cameras, relative to 35 mm film format as a reference. In the case of digital cameras, the imaging device would be a digital sensor. The most commonly used definition of crop factor is the ratio of a 35 mm frame's diagonal (43.3 mm) to the diagonal of the image sensor in question; that is, CF=diag35mm / diagsensor”</p>

<p>I think we agree but we are talking at cross purposes on the assumed Pentax 645 sensor size.</p>

<p>For the arbitrary ISO, well the point of it being a spreadsheet is you can put in any ISO you want to try. The screenshot happened to have the DxO low ISO figure in it as that was the last one I happened to type in.</p>

<p>I was just sharing the mathematical relationships between the systems for those that might be interested. I’m not commenting on why anyone would bother switching between systems.</p>

<p>Having said that I think I might agree with you about the Pentax 645 (44x33 sensor) vs full frame looking expensive for the difference you get. But then it’s not aimed at my type of photography (or my budget!).</p>

<p>Antonio, How do you get 0.77? How does it make a difference or are you just suggesting I should show more decimal places?</p><div></div>

<p>Matt/Antonio,</p>

<p>If you imagine two people side by side taking the same picture, one with DX, the other with FX. I think it’s widely accepted that the 1.5 crop factor makes 50mm on DX “the same” FoV as 75mm on FX. Most even agree that f2.8 in DX is “the same” as f4.2 in FX when also considering the DoF differences the sensors show in the final print.</p>

<p>But what most miss when comparing the two systems is that when taking a picture of the same subject is that once you have changed the aperture you need to change the ISO to match (because the available light is the same). Otherwise you would underexpose FX when trying to get the same image (match the DX FoV and DoF). The ISO row is the ISO to go with the aperture and shutter to match the exposures for the column.</p>

<p>In a way you’ve really just said a photograph taken with the same available light will show better sensor qualities when taken with settings that produce a shallower DoF.</p>

<p>It was really just an excersise to understand the system differences and physical interactions and I thought others may be interested in it. Like Wouter says, it's about what each system does best, worst or not at all - that makes or breaks the choice. The spreadsheet may help some understand how and why each system behaves like it does from a purely theoretical sensor/lens point of view. No considerations for any particular camera ergonomics modelled!</p>