to crop or not to crop?

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Archive 2011 · to crop or not to crop?

mjeffbr
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p.1 #1 · to crop or not to crop?

I have a tendency to always take into consideration the worst view of anything, I know it should not be like that, but anyways, one bad review and I start looking for alternatives, even if all the others say that thing is great.

Well, the reviewers at photozone seem to be pretty harsh when it comes to analyzing canon lenses on a FF body, even the so called “holy trinity” of primes has received some criticism

I do not know why the same lenses get much better reviews for crop sensor cameras (they post two reviews of each lens), but as he posts all the test results one should assume they have some credibility, even though I think for a moment that the same results could be taken as “better” simply because you have a crop, so for a crop shooter it’s ok, you should be thankful, but for a full frame you deserve more…

I was pretty convinced that FF was the way to go, but now I kinda have that doubt, an example: the 70-200 2.8 II is near perfect for FF, and flawless for Crops, the same goes to many other lenses, some are ok for FF, but very good for 1.6x cameras, like the almighty 85 1.2, which, according to them, is not so good for FF

I am well aware of the field of view differences, which can be a good or a bad thing, depending on your style

but there always seems to be more distortion, and all sorts of problems on the corners, like vignetting, light falloff, ca, and what frightens me the most = loss of sharpness

so for me the question is

To crop or not to crop?

Edited on Dec 09, 2011 at 02:17 PM · View previous versions

Dec 09, 2011 at 12:32 PM

mbaumser
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p.1 #2 · to crop or not to crop?

who are you going to believe, Photozone or your own lying eyes?

Look around this site and others. Do you see loss of sharpness on FF images.

Dec 09, 2011 at 12:41 PM

dalongfellow
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p.1 #3 · to crop or not to crop?

So, if I reword your question (to play devil's advocate), you're worried that your ability to take outstanding photographs will be limited by the compromises in FF? That you will be disappointed that you can't take better pictures than the best FF images you've seen on this site and others where you've seen FF camera images? For my part, I hope I get good enough that FF issues are what's holding me back.

Dave

Dec 09, 2011 at 12:47 PM

jcolwell
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p.1 #4 · to crop or not to crop?

I use the Canon fast L primes on FF cameras a lot. They're excellent.

I use a crop camera like the 1DIV when it offers something that the FF cameras don't offer, like 10 fps (waiting for the 1DX...). At any particular time, contemporary crop bodies offer more pixels-per-duck than FF bodies (which is a better index than equivalent focal length), but that's only part of the story.

mjeffbr wrote:
... one bad review and I start looking for alternatives, even if all the others say that thing is great.

You'll never be satisfied until you can put this behaviour aside.

mjeffbr wrote:
I am well aware of the focal lenght differences ...

There are no focal length differences, the smaller sensor in the crop body simply captures a smaller portion of the same image that a full frame body captures more of. The crop body appears to have a longer focal length because the image has a higher magnification when viewed at the same size as 'the same' image from a FF camera ('the same' meaning same lens and same distance from the subject).

Dec 09, 2011 at 12:54 PM

Hrow
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p.1 #5 · to crop or not to crop?

FF bodies are good for some things and croppers are good for others. If you don't know when to use which I wouldn't be too concerned about Photozone reviews.

Dec 09, 2011 at 01:06 PM

mjeffbr
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p.1 #6 · to crop or not to crop?

dalongfellow wrote:
So, if I reword your question (to play devil's advocate), you're worried that your ability to take outstanding photographs will be limited by the compromises in FF? That you will be disappointed that you can't take better pictures than the best FF images you've seen on this site and others where you've seen FF camera images? For my part, I hope I get good enough that FF issues are what's holding me back.

Dave

well, not really worried about my abilities (which are limited), but making the right choices and protecting my wallet from potentially unecessary expenses

if crop cameras can keep the qualities of the best lenses, eliminating some possible flaws (that seem to concentrate on the corners of FF's, like the sharpness) I can save money that can be invested in glass

though I can always trust my eyes I do not have access to all the lenses I am interested in, let alone theses lenses on two different bodies

Edited on Dec 09, 2011 at 02:05 PM · View previous versions

Dec 09, 2011 at 02:02 PM

mjeffbr
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p.1 #7 · to crop or not to crop?

Hrow wrote:
FF bodies are good for some things and croppers are good for others. If you don't know when to use which I wouldn't be too concerned about Photozone reviews.

well, when should I use a FF and not a crop?

always read you could do the same things with either, provided you take into account the field of view differences for the same lenses

Dec 09, 2011 at 02:05 PM

AGeoJO
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p.1 #8 · to crop or not to crop?

mjeffbr wrote:

but there always seems to be more distortion, and all sorts of problems on the corners, like vignetting, light falloff, ca, and what frightens me the most = loss of sharpness

so for me the question is

To crop or not to crop?

Here is my take - The folks at photozone concentrate more on the lens performance throughout the entire viewing field. To them, the ideal lens would have the same resolution (or sharpness, if you want to call it that way) in the outer corners as well as in the center. Such ideal lens doesn't exist. Period. Even the best lens manufacturer in the world cannot mass produce something like that in economic way. In a lot cases, especially in portraits, the lens' subpar performance in the corners or edges actually works to our advantage. You want the center to be reasonably sharp but you want the edges to be blurred, not only out of focus but with optical flaws that create a nice bokeh, letting you concentrate on your target. That's why a lot of folks prefer using largish aperture to capture portraits.

Admittedly, that doesn't apply to landscape photography in most cases. Generally, you want a sharp lens that performs uniformly well, as close as possible, at least, from the corner to the center in landscape photography. In order to get that, you want to stop down the lens 3-4 stops to bring the corner performance closer to that of the center and to increase the depth-of-field.

To crop or not to crop? Well, if you are after nice smooth bokeh, in general, you may want to use a FF camera. Not a direct correlation there but you tend to move in closer to your target to fill the frame more that way. A crop camera will be fine for landscape but the crop factor kind of takes away the wide angle effect from your lens and you have to compensate for that. I use crop cameras to get the reach in wildlife photography and use a FF camera for anything else.

Edited on Dec 09, 2011 at 03:33 PM · View previous versions

Dec 09, 2011 at 03:27 PM

Richard Nye
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p.1 #9 · to crop or not to crop?

I have a FF camera, 1.3X crop and 1.6X crop. I use the FF camera mostly because it brings out the best in the lenses. The lenses act like I expect them to, and I can get great control over DOF. I use 1.3X when I need 10 fps or a little more reach, and 1.6X when I need compactness for travel.

Dec 09, 2011 at 03:31 PM

eosfun
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p.1 #10 · to crop or not to crop?

If you don't know or can't appreciate the value of full frame images and you want to protect your wallet, you'd better go for a crop body. Crop bodies give great creative possibilities too and you probably first need to develop some skills and the feel for full frame "need". Full frame is the ultimate image quality tool (that is: relative in it's format and price class), but it comes at a price. Mastering DOF of high speed lenses is a much more challenging issue for example than control over the ultimate edges and corners and residual lens abberrations. If you need the very best image quality it is also in lenses going to be an expensive matter anyway, full frame or crop. I would not worry about image quality in corners from holy trinity lenses anyway.

Like Henry says if you don't know what to use a cropper for and what a full frame, don't worry about review sites. Photozone is one of the least useful review sites in my eyes anyway. I find their mix of objective measurement and subjective opinions very hard to understand. Better trust your eyes. Looking pBase photos and browsing our presentation forums, just like asking for advice here at FM, has been much more helpful for my buying decisions than any test site. In doubt I borrow or rent glass before buying. But no review based decisions.

Have EOSfun

Dec 09, 2011 at 04:05 PM

BluesWest
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p.1 #11 · to crop or not to crop?

what frightens me the most = loss of sharpness

What frightens me the most = threads like this

John

Dec 09, 2011 at 05:28 PM

mjeffbr
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p.1 #12 · to crop or not to crop?

BluesWest wrote:
what frightens me the most = loss of sharpness

What frightens me the most = threads like this

John

well, do not worry anymore!

next time I'll make sure I ask you beforehand if my doubts would potentially bother you sir...

Dec 09, 2011 at 05:46 PM

gdanmitchell
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p.1 #13 · to crop or not to crop?

A general rule to apply to "what you read on the web" - When some review or report seems to tell you that some gear that is used by thousands and thousands of photographers - many of whom might use it for their living - is really awful... someone is exaggerating or inventing stuff.

I don't know the particular review you are looking at, and it is possible that you might be misinterpreting it.

Also note that there are a bunch of variables that are often ignored or misinterpreted in many reports and reviews. One of my favorite is based on comparisons of 100% crops - where you might be looking at larger or smaller portions of the frame depending on pixel dimensions. The crop to FF comparisons are also fraught with potential ways to go very wrong.

Instead of focusing too much or reviews, ask yourself if these lenses are used by lots of photographers to make great photographs... and then move on.

Dan

mjeffbr wrote:
I have a tendency to always take into consideration the worst view of anything, I know it should not be like that, but anyways, one bad review and I start looking for alternatives, even if all the others say that thing is great.

Well, the reviewers at photozone seem to be pretty harsh when it comes to analyzing canon lenses on a FF body, even the so called “holy trinity” of primes has received some criticism

I do not know why the same lenses get much better reviews for crop sensor cameras (they post two reviews of each lens), but as he posts all the test results one should assume they have some credibility, even though I think for a moment that the same results could be taken as “better” simply because you have a crop, so for a crop shooter it’s ok, you should be thankful, but for a full frame you deserve more…

I was pretty convinced that FF was the way to go, but now I kinda have that doubt, an example: the 70-200 2.8 II is near perfect for FF, and flawless for Crops, the same goes to many other lenses, some are ok for FF, but very good for 1.6x cameras, like the almighty 85 1.2, which, according to them, is not so good for FF

I am well aware of the field of view differences, which can be a good or a bad thing, depending on your style

but there always seems to be more distortion, and all sorts of problems on the corners, like vignetting, light falloff, ca, and what frightens me the most = loss of sharpness

so for me the question is

To crop or not to crop?

Dec 09, 2011 at 09:38 PM

alundeb
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p.1 #14 · to crop or not to crop?

Comparing image quality between different formats is complicated. I find the principles described here to be the most useful ones:

http://www.josephjamesphotography.com/equivalence/

Dec 09, 2011 at 10:16 PM

mjeffbr
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p.1 #15 · to crop or not to crop?

alundeb wrote:
Comparing image quality between different formats is complicated. I find the principles described here to be the most useful ones:

http://www.josephjamesphotography.com/equivalence/

really nice, thanks

Dec 09, 2011 at 11:17 PM

cgardner
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p.1 #16 · to crop or not to crop?

There seems to be a technical obsession with pixel peeping edge-to-edge sharpness by some, but stop for a minute and consider the goal in cropping and composing an image is encouraging and predicting eye movement from the less important to the more important element in the photo.

It's easy to grasp how shallow DOF isolated a foreground object and pulls the viewer to it and holds their attention there. But the same dynamic is in effect subliminally when a lens creates an image that is a bit blurred and darker on the edges. Photographs with softer vignetted edges provide the viewer with subliminal clues that what is in the center is more important.

A sharp center / fuzzy edge dynamic in a photo mimics how our eyes and brain work. We see about 140° but only really concentrate on the center 2° at any point in time; the brain filters out the rest until our attention shifts. 2° is twice the width of your thumb held at arms length; about this wide at reading distance:

>>>>>>><<<<<<<<<<<

There's a physiological reason for our "tunnel vision". The color sensing cones are concentrated around the optic nerve in the center. The rest of the retina is covered by the rod cells which only sense a narrow band of wavelengths in the green region (they are not sensitive to red) and are about 3000x more sensitive to light than the cones. The higher sensitivity of the rods is why we can see at better at night with peripheral vision. The fact the are not sensitive to red is why red lights are used on instruments at night; preserve night vision.

How this relates to edge sharpness is that in a photo when the viewer is concentrating on the center of the photo the rods of the eyes are reacting to any distractions they detect in the corners. A way to prevent objects on the edges of photos from becoming distractions are to: 1) crop them out, 2) blur them, or 3) make them blend into the overall background and contrast less. Part of what makes vintage images have a more organic and less clinical feel than today's digital images was the fact the lenses were soft and vignetted on the edges.

What I'm suggesting is that when selecting gear look beyond obsessing over the technical specs to see the bigger perceptual goals of the exercise. YMMV, but I don't obsess over edge sharpness. What I care about is image resolution and contrast in the center part of the frame where I compose the important focal points of my images. So I bought expensive L lenses to get that then wind up blurring and vignetting the edges and selectively softening other areas in most shots I take because the lenses record things too uniformly sharp for my tastes— a sea of boring sameness. I want to see the sparkle in the eyes, not every pore on the nose or stitch in the clothing. In portraits I sharpen the eyes and mouth and blur everything else by degrees. For scenics I keep the focal point sharp and soften / vignette the edges, but not to the point that it is noticed; just enough to provide a subliminal clue that the stuff in the middle is more important.

Regarding distortion, there is different cause and effect involved. Edge distortion is the result of anastigmatic correction in the lens design. A simple lens, like the eye, focuses on a spherical plane. That explains why eyes are round not cubes. A simple lens projecting an image on a flat plane will only be in focus in the center (astigmatism) so lens makers learned to add corrective elements to alter the path of the light so the edges would be in focus. But that correction distorts the image.

By way of analogy the way a simple lens focuses on a flat plane like cutting a tennis ball in half and nailing just the center to a board. A lens with anastigmatic correction is like taking the equator of the ball and stretching and nailing it flat — the stretching is more apparent on the extreme edges.

Lenses of all focal lengths are affected but the effects of the correction are noticed most in shorter focal lengths because more correction is needed to get the edges in focus on the flat plane. An EF lens on a 1.6 crop body will put more of the corrected edges of the lens image footprint outside the smaller sensor.

Dec 10, 2011 at 12:59 AM

skibum5
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p.1 #17 · to crop or not to crop?

mjeffbr wrote:
I have a tendency to always take into consideration the worst view of anything, I know it should not be like that, but anyways, one bad review and I start looking for alternatives, even if all the others say that thing is great.

Well, the reviewers at photozone seem to be pretty harsh when it comes to analyzing canon lenses on a FF body, even the so called “holy trinity” of primes has received some criticism

I do not know why the same lenses get much better reviews for crop sensor cameras (they post two reviews of each lens), but as he posts all the test results one should assume they have some credibility, even though I think for a moment that the same results could be taken as “better” simply because you have a crop, so for a crop shooter it’s ok, you should be thankful, but for a full frame you deserve more…

I was pretty convinced that FF was the way to go, but now I kinda have that doubt, an example: the 70-200 2.8 II is near perfect for FF, and flawless for Crops, the same goes to many other lenses, some are ok for FF, but very good for 1.6x cameras, like the almighty 85 1.2, which, according to them, is not so good for FF

I am well aware of the field of view differences, which can be a good or a bad thing, depending on your style

but there always seems to be more distortion, and all sorts of problems on the corners, like vignetting, light falloff, ca, and what frightens me the most = loss of sharpness

so for me the question is

To crop or not to crop?

One thing to keep in mind is that the photozone guy has an unhealthy obsession with assigning lens star ratings for optics based upon f/1.0-1.4 ratings at the far edges, if the lens offers the chance. So despite the 24 1.4 II utterly destroying the 24-105L and other lenses when comparing them at the same apertures, even going by his results as well, he goes crazy on the 24 1.4 II for having very soft edges on FF AT WIDE OPEN and he rates it with less stars for optical quality than stinker of a zoom and even his good of that zoom doesn't touch any of his data for the 24 1.4 II! Ridiculous. I mean show us a 24mm lens that has sharp FF edges at f/1.4? Where is this magical lens? It doesn't even exist, at least not for less than some tens of thousands of dollars, if even.

That said I find his results, the numerical ones, not necessarily his overall star ratings (and I have to say it seems on most sites it's the charts not the overall ratings that are most useful) to more often match what I've seen myself that the TDP results which seem to very often not match what I've seen myself all that much.

So if he says the 85 1.2 is trash on FF he probably means that like almost any 85 1.2 it will have a bit soft far edges on FF even if it is all the same one of the sharpest lenses ever made by f/2.5 and probably has mad sharp edges by f/3.2 or f/4 even on FF.

So I say look at this plots for distortion and CA and lens sharpness and ignore his overall ratings and some of his text. I find his data to more often match what I've seen than probably any single other site. Of course not everything is a match. Lens testing requires ASTONISHING precision and it's sooooo easy to get wrong and then copies really do vary and he mostly relies on copies people send in which could lead to biases. And you know whether distortion matters or not at all, whether longitundal CA matters, whether you need sharpness at edges when stopped down or not, etc.

Distance to target matters too, he once went outdoors to get good distance for his 300 2.8 test and with the distance and outdoor air shimmer effects he got it to score some of the worse 300mm scores of the entire canon line hah before he tossed out the result a short while later.

Dec 10, 2011 at 01:41 AM

Sunny Sra
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p.1 #18 · to crop or not to crop?

Marcio...just take some pictures man...

Dec 10, 2011 at 01:50 AM

skibum5
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p.1 #19 · to crop or not to crop?

And don't forget that some of difficulty in using the extended FF edges is mitigated by having a larger surface area over which to capture detail so sometimes it can tail off at the edges and yet still almost match or match or even exceed total detail grabbed by APS_C, although granted not always.

And also that you often care about edges more often when shooting well stopped down where a higher number of lenses do o enough at the edges that the large sensor area to capture details more than makes up for any losses. granted not always, but often enough for many.

Dec 10, 2011 at 01:51 AM

scalesusa
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p.1 #20 · to crop or not to crop?

If you read the photozone reviews closely, you will see some lenses fare better on ff than crop, and the converse.

There is always a tradeoff, FF has lower high ISO noise, and a wider angle is possible using the same lens while in the same position. The IQ of the images is usually noticibly better.

These are really fine technical points, and Klause at Photozone takes a strict stand, and tells it like it is, which troubles some, or for those like myself, its just a fact and I will know what to expect. So far, he has been right on. I've had five 24-70mm lenses, for example, and while they were good, they did not meet my expectations. all are gone.

That said, the other 99% of the image quality depends on the photographer. Any of the modern DSLR cameras will do great in the hands of a knowledgable photographer. You cannot buy your way into great images.

Dec 10, 2011 at 02:06 AM

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