How much sharpness is reasonable to expect at various zoom/crop levels?

[SCoombs]

I have a somewhat nuanced question here and I'm hoping I can get it across well because in spite of my title I'm not really trying to talk about cropping here. Rather, I'm trying to figure out how sharp we can reasonably expect a lens to be and I bring up zooming/cropping because just about any lens is going to look pretty sharp if we're just looking at a full size image.

In doing lens reviews and comparisons, Steve usually zooms in to 200% in Lightroom to compare, and in fact most people talking about this sort of stuff, both professional and everyday folks on forums tend to zoom in to 200% for these sorts of comparisons. When doing so, they always look to me pretty good - clearly upscaled, but given it's a 200% zoom nevertheless pretty smooth. I have never had a lens that would result in anything comparable.

Yet I've had lenses that are theoretically pretty sharp. FoCal rated my 200-500 as high as 94 compared to other copies of the same lens, meaning it's one of the sharpest copies. I have also shot with the 180-600, which it rated at an 81 - not nearly as good, but still "above average," meaning it should be better than most other copies. I recently acquired a 500pf, which was rated at a 91 - not quite as high as the 200-500, but this is compared to other 500pfs, and given the lens' reputation one would expect one rated 91 against other copies that it ought to be pretty sharp. Note that as absolute measures I don't necessarily put a lot of stock in FoCal's ratings here, but as general relative measures I think it's reasonable to be confident that a lens rating a 90+ is probably a pretty good copy and one in the low 80s is probably decent and at least not especially poor.

In any case, my observation on pretty much all of my long telephoto lenses (with shorter lenses like I use for portraits the same doesn't seem to apply) that if I zoom to about 67% in LR, things will look pretty good, but if I go to 100% they can start looking very soft or even just downright messy/borderline pixelated. Here are three examples from my 500pf, cropped to match about the size of a 67% and a 100% zoom.

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Frankly, having looked at these full screen now even the 67% ones are starting to look just a bit rougher to me, but let's continue nonetheless.

Now the squirrel shot was a DX frame filling shot. The others were smaller in the frame, but honestly not that small (here's a link to the final version of the robin, which is jut a relatively minor crop from the original DX shot https://www.facebook.com/photo/?fbid=122136763556123752&set=pb.61553712560245.-2207520000)

So my question is in essence this: have I just managed to somehow get subpar copies of all of my lenses (in spite of FoCal's ratings)? Or is the sort of sharpness level and the sort of change in apparent sharpness as the image is viewed at larger sizes more in line with what is reasonably expected?

(Edit: something went funny with the way the squirrel photos were output and it looks like the sizes may not be quite right, but I can't fix it right now).

 

[Cameron T]

I never go past about 75% because pixel peeping is bad for the soul. You might be overly critical.

There's a lot to it, but generally going past 1:1 on your monitor is where it gets bad worse, and not worth doing.

 

[SCoombs]

I never go past about 75% because pixel peeping is bad for the soul. You might be overly critical.

There's a lot to it, but generally going past 1:1 on your monitor is where it gets bad worse, and not worth doing.

I think it's hard for a group of people agree on pixel peeping other than to agree that there are a lot of different and even subtly different opinions. I'd rather not open that can of worms here so I'll try to be clear that the only reason I mention specific percentages here is as a way of giving a specific frame of reference around which to have a discussion and to compare to others who regularly show what seem to me to be stronger results even at 200%.

As for viewing 1:1, I'd agree although unless we're talking about super crazy crops even a 100% zoom shouldn't surpass a monitor's native pixels.

 

[Matt N]

The sharpness levels of your examples are in line with my experience and expectations. None of the lenses you listed are premium lenses, which is where you would see a noticeable difference in sharpness ( in my experience). I’ve rented several high end lenses and I can tell a huge difference in sharpness. I always assumed that’s one of the reasons to pay premium prices.

You may not be experiencing this at shorter focal lengths because perhaps your shorter lenses are premium. It’s not that they are cheap, but they are cheap-er. For example, a premium 24-70 is $3000, but a premium 600 is $13000 or more.

Again, this is just my experience from renting several lenses across the whole range of prices and three different brands.

 

[Matt N]

There are some exceptions though. My Canon 100-500 is Very sharp, as is my 800pf. But neither come close to the Sony 600 f4 that I rented. Cropped photos on that blew me away. But maybe I just have too small of a sample size. who knows.

 

[Nimi]

There are some exceptions though. My Canon 100-500 is Very sharp, as is my 800pf. But neither come close to the Sony 600 f4 that I rented. Cropped photos on that blew me away. But maybe I just have too small of a sample size. who knows.

The 800 might be the sharpest lens on the market right now, at any price.

 

[Camatose]

In any case, my observation on pretty much all of my long telephoto lenses (with shorter lenses like I use for portraits the same doesn't seem to apply) t

It's unlikely you're shooting portraits at the same distance. The atmosphere will cause issues with clarity, and distance must be taken into account.

 

[SCoombs]

Duplicate poat

 

[SCoombs]

The sharpness levels of your examples are in line with my experience and expectations. None of the lenses you listed are premium lenses, which is where you would see a noticeable difference in sharpness ( in my experience). I’ve rented several high end lenses and I can tell a huge difference in sharpness. I always assumed that’s one of the reasons to pay premium prices.

You may not be experiencing this at shorter focal lengths because perhaps your shorter lenses are premium. It’s not that they are cheap, but they are cheap-er. For example, a premium 24-70 is $3000, but a premium 600 is $13000 or more.

Again, this is just my experience from renting several lenses across the whole range of prices and three different brands.

Hmm, while the two zooms are definitely consumer grade the 500pf is normally considered fairly high end in terms of image quality, even if still not quite to the level you see from the true exotic level of lens, and for whatever it's worth certainly its MTF chart is very similar to the highest level lenses as compared to any of the zooms or consumer grade stuff (for instance, it's extremely similar to that of the 800pf, so vaunted in a few posts above).

As for shorter lenses, really most of them are not especially high end. The theoretically best of them is my 85/1.8 S, which though an S lens is considered nowhere near the level of the 85 1.2. Then I have a 70-180 - definitely the "cheap" version of that focal range. Finally a 40mm f2, which is essentially a kit lens. It's not that these are all perfectly sharp so muc as it is that I don't notice substantial differences in sharpness with them as I zoom from, say 50% to 67% to 100% as I do when zooming in with the longer stuff.

 

[Matt N]

Noise can affect our perception of sharpness when cropping. Steve has some videos on cropping and noise. So larger aperture lenses may “appear” to be sharper when cropping because there is less noise.

I actually think your 100% crops look pretty good and would have no problem sharing those at those crop levels. But we each have our own preferences.

 

[SCoombs]

It's unlikely you're shooting portraits at the same distance. The atmosphere will cause issues with clarity, and distance must be taken into account.

Often true, but in many cases - like all.of the examples I've shared here - they are at about the same distance as I'd shoot a portrait with no ill effect.

 

[AlainCh2]

@SCoombs > I can share two of my lenses experience 70-300E & 180-600Z

Zf <Dx Mode> + 70-300E @450mmEq [PP-Crop 100>50] >>8mt

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Zf <Fx Mode> 180-600Z @370mmEq [PP-Crop 100>70] >>2mt

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Zf <Fx Mode> 180-600Z @600mmEq [PP-Crop 100>30] >>32mt

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Z30 <+1.4TC> 180-600Z @1260mmEq [PP-Crop 100>95] >>2.2Km

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Z30 <+1.4TC> 180-600Z @1260mmEq [PP-Crop 100>90] >>70mt

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When AF focus gets it I have sharp images, otherwise I'm viewing images like the last one....

( I Use a 65" monitor and peep @400% )

 

[SCoombs]

Noise can affect our perception of sharpness when cropping. Steve has some videos on cropping and noise. So larger aperture lenses may “appear” to be sharper when cropping because there is less noise.

I actually think your 100% crops look pretty good and would have no problem sharing those at those crop levels. But we each have our own preferences.

True, though I've observed this with very low ISO, very low noise photos.

 

[Matt N]

I’m not familiar with FoCal. How does that work?

 

[SCoombs]

I’m not familiar with FoCal. How does that work?

You set the camera on a tripod and connect your computer or cell phone via USB. There is a target they have that is set up and FoCal is able to take control of the camera and take a bunch of photos, unfocusing after each so the AF engages again for each photo. It then can do lots of different things involving evaluating the camera/lens. A lot of people use it to do AF fine tuning since it can check a series of photos at different AF fine tune settings and hone in on thr best one.

One thing it does is compare your lens/camera to all other such combinations other people have used. Obviously this means the rating is only as good as their data set, but from what I understand it's fairly widely used and plenty of people who would want the highest quality stuff for higher level work use it so I'd expect the dataset to be at least relatively worthwhile for making a rating with some value.

 

[Matt N]

You set the camera on a tripod and connect your computer or cell phone via USB. There is a target they have that is set up and FoCal is able to take control of the camera and take a bunch of photos, unfocusing after each so the AF engages again for each photo. It then can do lots of different things involving evaluating the camera/lens. A lot of people use it to do AF fine tuning since it can check a series of photos at different AF fine tune settings and hone in on thr best one.

One thing it does is compare your lens/camera to all other such combinations other people have used. Obviously this means the rating is only as good as their data set, but from what I understand it's fairly widely used and plenty of people who would want the highest quality stuff for higher level work use it so I'd expect the dataset to be at least relatively worthwhile for making a rating with some value.

Do you have a link to this product? When I search for FoCal, I get results for “focal” which is not helpful.
I may want to try this out.

 

[SCoombs]

Do you have a link to this product? When I search for FoCal, I get results for “focal” which is not helpful.
I may want to try this out.

If you can't find it I can grab a link later - just have a second now. Search for "Reikan Focal" and it should come up.

I use the cell phone version which is cheaper but does less. I've considered the desktop version.

 

[Matt N]

Does FoCal take pictures at different apertures? Some lenses are sharper stopped down. Not knowing anything about the software, I wonder if the rating you are getting is for your lens but at a different aperture than you normally shoot at? I’m just trying to brainstorm some more possibilities for you.

 

[StefanSC]

So my question is in essence this: have I just managed to somehow get subpar copies of all of my lenses (in spite of FoCal's ratings)? Or is the sort of sharpness level and the sort of change in apparent sharpness as the image is viewed at larger sizes more in line with what is reasonably expected?

It looks to me that you are getting moire in the first two shots ... that for me is a sign of a very sharp lens.

Other than that, in the field, there are so many variables that determine how much detail you capture and how sharp and cropable an image is that I wouldn't trust any software and I would take what reviewers claim with a big ol' fist of salt.

Just to mention a few of the things that I've encountered just in the past few months that visibly impacted the sharpness of my output:

- focus precision.
- distance to subject.
- atmospheric conditions.
- light quality, quantity and direction.
- background quality, type and brightness.
- setting used to capture the shot.
- if the subject is wet or not.
- texture of the subject and how that interacts with noise reduction software.
- actual colors of the subject.

and so on...

And when I shot this comparison between a lens that reviewers say it is one of the sharpest available and one that is bottom of the pile in it's class, yet I can hardly tell them apart... :

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... I kind of put my hands up and went: if it feels right to me and gets me the shot, then that's all that matters and I won't waste my time worrying about how sharp my lenses are.

 

[SCoombs]

Does FoCal take pictures at different apertures? Some lenses are sharper stopped down. Not knowing anything about the software, I wonder if the rating you are getting is for your lens but at a different aperture than you normally shoot at? I’m just trying to brainstorm some more possibilities for you.

I'm pretty sure it uses the widest aperture since that's normally advised for calibration as it makes the DoF most shallow and means you're getting a more precise look at where focus is.

The desktop version can compare at other apertures to find a specific lens' sharpest aperture.

Fwiw I've experimented a lot with aperture, including shooting test charts, and I've found my 200-500 and 500pf don't really change sharpness in a really noticeable way as you stop down while my 180-600 sharpens considerably as you stop down.

 

[SCoombs]

It looks to me that you are getting moire in the first two shots ... that for me is a sign of a very sharp lens.

Do you mean the two of the robin, or the robin and the cardinal? Fwiw I can see it on the robin's back but it's only visible as moire I the downsized forum version. In my computer it appears as some iridescent feathers but not moire.

Other than that, in the field, there are so many variables that determine how much detail you capture and how sharp and cropable an image is that I wouldn't trust any software and I would take what reviewers claim with a big ol' fist of salt.

Just to mention a few of the things that I've encountered just in the past few months that visibly impacted the sharpness of my output:

- focus precision.
- distance to subject.
- atmospheric conditions.
- light quality, quantity and direction.
- background quality, type and brightness.
- setting used to capture the shot.
- if the subject is wet or not.
- texture of the subject and how that interacts with noise reduction software.
- actual colors of the subject.

and so on...

And when I shot this comparison between a lens that reviewers say it is one of the sharpest available and one that is bottom of the pile in it's class, yet I can hardly tell them apart... :
View attachment 86442


... I kind of put my hands up and went: if it feels right to me and gets me the shot, then that's all that matters and I won't waste my time worrying about how sharp my lenses are.

I care in part because while I try to avoid it been I usually have to crop at least a little bit and I am finding that I sometimes notice the degradation even with what seem to be crops that are not especially large or when viewing the photo at any kind ofnlsrher size - eg, even a DX sized image viewed full screen on the sort of TV sometimes used as an information panel somewhere.

I also care because the reality is that as you've noted a lot of stuff interferes with image quality. I want to as far as I can afford have the best "raw starting point" so that when things do interfere, the lens is at least not making it significantly worse.

Finally, the reality is unfortunately I am doing much of this in my own without real prospects for any sort of mentor or other experienced people around to learn from or take advice from. As such I have to struggle with the dynamics of my own confidence vs the quality of my equipment, etc. Make no mistake I'm by no means new at this l, but I still have learned everything I have on my own and so often when I am not getting good results I have no way to with much confidence say whether there is something I cam do differently or whether I am running up against what is beyond my control. This is a big reason I want to be as confident in the equipment as possible so that there are fewer reasons to doubt things from that perspective.

 

[fcotterill]

I no longer lose sleep over concerns over sharpness of the modern Nikon telephotos. This includes almost all the G, E and Z primes (admittedly some of these have to be stopped down ~1 stop to achieve maximum contrast); and this includes most of the tele-zooms, which Nikon has released since and including the 70-200 f2.8E FL.

"Even" the 24-200 Z kit zoom delivers excellent results on wildlife subjects. The 200-500 f5.6E may be a controversial member of this club, but the plethora of excellent images taken worldwide speak loudly.

A few years ago, Canadian Pro flagged the importance of Aperture Independent Sharpness, particularly wide open of the new Nikkor Telephotos. His conclusions were based on testing Nikon's recent telephoto zooms, notably the 180-400 f4E TC14. This factor maybe more important in many cases.

The above generalization obviously assumes minimal cropping and sound techniques. Heavy crops take a heavy toll on image quality, particularly of distant subjects. This also brings us to the less widely discussed influence of subject distance, where the best exotics stand apart (Atmospherics permitting obviously). The 800 f5.6E FL is the pertinent exemplar of this distinction.

Other variables besides cost are as important in selecting one's optical battery: including ergonomics, versatility, lens speed. We're most fortunate that reliable committed reviewers publish their tests on telephotos (and Teleconverters): Brad Hill, Photography Life, @Steve, Thom Hogan

 

[SCoombs]

I no longer lose sleep over concerns over sharpness of the modern Nikon telephotos. This includes almost all the G, E and Z primes (admittedly some of these have to be stopped down ~1 stop to achieve maximum contrast); and this includes most of the tele-zooms, which Nikon has released since and including the 70-200 f2.8E FL.

"Even" the 24-200 Z kit zoom delivers excellent results on wildlife subjects. The 200-500 f5.6E may be a controversial member of this club, but the plethora of excellent images taken worldwide speak loudly.

A few years ago, Canadian Pro flagged the importance of Aperture Independent Sharpness, particularly wide open of the new Nikkor Telephotos. His conclusions were based on testing Nikon's recent telephoto zooms, notably the 180-400 f4E TC14. This factor maybe more important in many cases.

The above generalization obviously assumes minimal cropping and sound techniques. Heavy crops take a heavy toll on image quality, particularly of distant subjects. This also brings us to the less widely discussed influence of subject distance, where the best exotics stand apart (Atmospherics permitting obviously). The 800 f5.6E FL is the pertinent exemplar of this distinction.

Other variables besides cost are as important in selecting one's optical battery: including ergonomics, versatility, lens speed. We're most fortunate that reliable committed reviewers publish their tests on telephotos (and Teleconverters): Brad Hill, Photography Life, @Steve, Thom Hogan

I'm curious to hear more about the role of subject distance.

I have seen this discussed a lot with some claiming that it doesn't matter - only size in the frame. I had always felt with my 200-500 that at greater distances it was weaker regardless of size in the frame.

Having gotten a 500pf, I've found one of the most notable differences to be that I think it's sharpness holds up better for subjects at greater distances than the 200-500 or 180-600.

 

[Cameron T]

I'm curious to hear more about the role of subject distance.

I have seen this discussed a lot with some claiming that it doesn't matter - only size in the frame. I had always felt with my 200-500 that at greater distances it was weaker regardless of size in the frame.

Having gotten a 500pf, I've found one of the most notable differences to be that I think it's sharpness holds up better for subjects at greater distances than the 200-500 or 180-600.

Of course distance matters, the more air you're trying to look through the higher odds that it'll be worse due to normal impacts, even if there isn't huge temp differentials, etc.

The sharper the lens to start with, the less it's impacted by this (but all lenses are).

 

[Matt N]

I also think another phenomenon occurs when comparing subject distance and size.

Let’s say you have a small cat that fills the frame. And another photo of an elephant that fills the frame. Often we look at things like hair, feathers, or eyelashes to see if something is sharp. On the cat the eyelashes are much larger proportionally to the image size than the elephant eyelashes. The elephant hairs and eyelashes have significantly less pixels on them and may appear less sharp.

So I agree that subject size plays a large part in our perception of sharpness.