What's better: move in close, or shoot from a distance and crop?

[Archibald]

On the original pictures the difference in the details is not as large as you'd first think. Look at the leaf, not the bug! I don't know what the problem is with the bug - it may be out of focus or maybe it moved - but the leaf has pretty good detail. The problem with noise is obvious, though. That depends on the resolution you have inside the cropped area. I've noticed that R5 II is pretty forgiving on that issue ... and good DR helps as well.

I don't know for sure what the contributors are to the IQ loss, but focus error seems unlikely considering the leaf borders are in focus and there is good DOF. Motion blurring is possible, but I don't see those characteristic motion streaks. Therefore motion blur does not seem to be significant. What I'm left with is diffraction.

And so far I neglected lens aberration, so we must include that possibility too. I don't know how to recognize that, though.

As for noise, it is the same in the two images in an absolute sense (pixel-level). It just gets magnified when cropping.

 

[JKT]

I'll have to disagree with the focus. I get the feeling the left side of the leaf is closer than the right side. Then on the close picture you have hit the focus on the bug and only the closest part (left) of the leaf is in focus. On the other picture the focus seems to cover the whole leaf, but it seems to miss the bug in front of it.

On the noise I agree. As long as you have sufficient resolution on the crop (considerably larger than the display size), the noise doesn't show. In this case you don't and it does.

 

[Archibald]

I'll have to disagree with the focus. I get the feeling the left side of the leaf is closer than the right side. Then on the close picture you have hit the focus on the bug and only the closest part (left) of the leaf is in focus. On the other picture the focus seems to cover the whole leaf, but it seems to miss the bug in front of it.

On the noise I agree. As long as you have sufficient resolution on the crop (considerably larger than the display size), the noise doesn't show. In this case you don't and it does.

It does look that way. In the first image (with shallower DOF), the left tip of the leaf and the front of the bug seem to be sharpest. This despite the bug seeming to be more forward. But in the second (cropped) image, everything seems to be about equally sharp... so I don't know.

Best to repeat the experiment with better control of focus.

 

[Archibald]

Nope. You are not taking something essential into account: the angle of view for a given focal length, which is determined by sensor size and affects depth of field. There are lots of posts online explaining the impact of sensor size on DOF, e.g., https://fstoppers.com/education/understanding-how-sensor-size-affects-depth-field-312599. That one also goes into the effect of distance to the subject. For a more technical explanation, you can look here: https://bobatkins.com/photography/technical/digitaldof.html.

I totally agree that cropping and smaller sensors give more DOF.

 

[Wilt]

It isn't, unless the two cameras have the same pixel density, which they rarely do.

The blur circle (a.k.a CofC) is generally NOT altered by the pixel density...a Canon 5D does not have different DOF depth than a Canon 5DIV, for example, although their pixel density is very different.

OTOH, sensor size does alter the DOF characteristics, but that is only because the effective Magnification -- at the focal plane -- is not the same!

• Magnification: The proportion between the size of the subject image on the camera sensor and its real size.

and for macro work, the formula Total DOF = 2 * C * N * (m + 1) / m² provides a more accurate estimation of the depth of field...there is no other factor pertaining to DOF other than CofC and magnification and f/number.

...yet while the CofC changes for different sensor sizes, that is only because the enlargement magnification factor is different to fill frame; but at the same final priint size...if you are viewing the same subject at the same size on the same final print size, the DOF is THE SAME again!

 

[paddler4]

The blur circle (a.k.a CofC) is generally NOT altered by the pixel density...a Canon 5D does not have different DOF depth than a Canon 5DIV, for example, although their pixel density is very different.

OTOH, sensor size does alter the DOF characteristics, but that is only because the effective Magnification -- at the focal plane -- is not the same!

• Magnification: The proportion between the size of the subject image on the camera sensor and its real size.

and for macro work, the formula Total DOF = 2 * C * N * (m + 1) / m² provides a more accurate estimation of the depth of field...there is no other factor pertaining to DOF other than CofC and magnification and f/number.

...yet while the CofC changes for different sensor sizes, that is only because the enlargement magnification factor is different to fill frame; but at the same final priint size...if you are viewing the same subject at the same size on the same final print size, the DOF is THE SAME again!

Perhaps I wasn't being specific enough. I wasn't referring to CoC. You had posted that cropping "is the equivalent of shooting with a smaller format sensor." I said it is not. One reason is the typical difference in pixel density. When you crop macro from FF, you get relatively few pixels on the subject. If you crop severely enough, this alone will produce precisely what you showed: a relative lack of detail and sharpness, and an increased appearance of noise. This is particularly obvious if you have to crop a lot, that is, if the critter doesn't come close to filling the APS-C frame.

If you do the arithmetic for most pairs of APS-C and cropped FF, the difference is usually huge.

As I said, my experience with this is why I virtually never use my nifty R6 II for bugs. The otherwise vastly inferior 7D 1 generally produces better bug macros.

So one answer to your question is that in macro work, if you have a large difference in pixel density, cropping from FF will often produce a noticeably inferior image. This is particularly obvious in prints because on-screen images benefit from the low resolution of most screens.

BTW, the importance of fine detail in bug macros makes this more important. That's the reason my default is to add a 36mm extension tube to my 100mm macro if I'm shooting moderate sized or small bugs. It's a pain in terms of reduced working distance, but it means much less cropping. E.g., this was taken with the 7D, 100mm macro, 36mm extension, f/13, single image (no stacking):

 

[Capn Jack]

The blur circle (a.k.a CofC) is generally NOT altered by the pixel density...a Canon 5D does not have different DOF depth than a Canon 5DIV, for example, although their pixel density is very different.

OTOH, sensor size does alter the DOF characteristics, but that is only because the effective Magnification -- at the focal plane -- is not the same!

• Magnification: The proportion between the size of the subject image on the camera sensor and its real size.

and for macro work, the formula Total DOF = 2 * C * N * (m + 1) / m² provides a more accurate estimation of the depth of field...there is no other factor pertaining to DOF other than CofC and magnification and f/number.

...yet while the CofC changes for different sensor sizes, that is only because the enlargement magnification factor is different to fill frame; but at the same final priint size...if you are viewing the same subject at the same size on the same final print size, the DOF is THE SAME again!

Hi Wilt!
1) Please cite whatever source you are using.
2) Define your terms.

With respect to this:
"OTOH, sensor size does alter the DOF characteristics, but that is only because the effective Magnification -- at the focal plane -- is not the same!"
You aren't explaining things very well. If I had an R5 and took an image in full frame mode, the subject would have a certain size projected onto the sensor. If I take the same image on that camera, changing nothing except using crop mode, that projection would be the same size on that sensor. The DoF would be the same.

 

[Archibald]

Perhaps I wasn't being specific enough.

No, you are being too specific. Pixel density has nothing to do with DOF.

 

[paddler4]

No, you are being too specific. Pixel density has nothing to do with DOF.

Did you read what I wrote? I didn't write about DOF; I wrote about loss of detail and apparent noise. And if you look at your OP, you will see that you weren't asking about DOF. You posted:

The far shot definitely has more DOF. That is a benefit. However, the rendition of detail is not very good in the far image. This could be due to focus error, or motion, or increased diffraction, or a combination of all three.

"The resolution of detail is not very good..." Yes, and I explained one of the main reasons why that is so.

Your title question was "what's better: move in close or shoot from a distance and crop?" I explained why it's often better to move in close.

I won't bother continuing with this thread.

 

[Archibald]

@paddler4 , I'm sorry, but my mind is not able to follow your arguments easily. As to the point that pixel density explains the loss of detail, I'm pretty sure that is not the main reason.

 

[RhodyPhotos]

BTW, the importance of fine detail in bug macros makes this more important. That's the reason my default is to add a 36mm extension tube to my 100mm macro if I'm shooting moderate sized or small bugs. It's a pain in terms of reduced working distance, but it means much less cropping. E.g., this was taken with the 7D, 100mm macro, 36mm extension, f/13, single image (no stacking):

Wow, this looks great. Was there any cropping involved?

 

[paddler4]

Wow, this looks great. Was there any cropping involved?

I’d have to go back to Lightroom to check for sure, but I don’t think there was much. That’s why I use extension tube much of the time. The greater magnification allows me to come closer to filling the frame with the subject.

 

[Wilt]

Perhaps I wasn't being specific enough. I wasn't referring to CoC. You had posted that cropping "is the equivalent of shooting with a smaller format sensor." I said it is not.

Ah, I was responding only within the context of the OP question, which centered on the question of Depth of Field effect of moving back with longer FL. A reply mentioned larger/smaller format, and my response was again within only the context of Depth of Field.
The context of IQ and the effects of increased detail are not contested by me, but I will point out that one MUST consider the detail resolution capability of the LENS itself, rather than always assume that better pixels/millimeter of sensor will always result in better detail resolution.
Factoring out digital resolution discussions, [shooting farther back and cropping] or [shoothing farther back with longer FL] or [changing format size] will resulting in (specifically) the same DOF as shooting closer, when all images result in SAME SIZE rendition of the subject on the final print...which is determined by the eye's ability to detect out-of-focus blur (shooting with same aperture size for all shots)

 

[paddler4]

@paddler4 , I'm sorry, but my mind is not able to follow your arguments easily. As to the point that pixel density explains the loss of detail, I'm pretty sure that is not the main reason.

Sorry I got cranky about this.

A number of factors might be at play, but the problem of loss of detail from severe cropping is common when people are novices at bug macro. It's very difficult to get close enough to get photos like the one I posted. I've been shooting bugs for years, and most of my captures are still junk that I discard. So many people give up and think, 'well, I can just crop'. The answer is: yes, up to a point, but if you crop severely enough, deteriorations in detail and greater noise will result.

I should have made it clear that you can push cropping pretty far, at least if you use noise reduction if needed and are displaying only on a screen. I'll post a pair I took 15 years ago with a 50D, which was a 15 MPX camera. The first has little cropping, while the second is cropped to about half the original to show the eyes better. The second is not the sharpest, but it's still fine for a screen.

However, this this problem is worse for FF cameras, given a similar pixel count, because at any given level of magnification, the FF will have fewer pixels on the subject to begin with.

 

[Archibald]

Yes, the second is good but is starting to show signs of image degradation.

As we crop, DOF increases and so does diffraction. I'm not saying that that statement is true in all cases, because as we seasoned debaters know, DOF is a sneaky quantity, and lovely contradictory things can be said about it. To wit:

DOF is deeper with a wide angle lens, right? Yes, that is our experience. Yet in macro photography, shooting pics with the same framing, DOF is the same regardless of lens focal length. And that is why macro photographers don't try to gain DOF by going to short focal lengths.

Small sensors are well known to have more DOF. But that is when the aperture and framing are the same. Big sensors have more DOF when the shooting distance and aperture are the same. Yes they do.

In the example in the first post of this thread, the comparison is between a near shot and a far shot, both taken with the same lens and same aperture. The far shot is then cropped to give the same framing. Under these conditions, the cropped pic has quite a bit more DOF.

This can be useful if we want to increase DOF. But in photography, we never get something for nothing, and everything is a compromise. While we win with DOF, we lose with diffraction. And IMO that is the main reason the IQ is worse in my far pic. Pixellation is not a significant issue in this case. The Airy disk in the images is way bigger than a pixel.

 

[paddler4]

There's a lot here.

For the best explanation of sensor size and DOF I've ever seen, read Bob Atkin's old post: https://bobatkins.com/photography/technical/digitaldof.html. Small sensors have more DOF under some circumstances. His post is fairly complicated, but all you really need is the bullet points at the beginning or end.

DOF is deeper with a wide angle lens, right?

For the most part, no. For a good explanation, see https://www.cambridgeincolour.com/tutorials/depth-of-field.htm. [Warning: that website is having problems, and sometimes it is VERY slow to load]. The popular misconception that DOF is inversely related to focal length is because of the different framing, that is, the different angle of view. If you move yourself so that the framing is identical, DOF is pretty much the same. This is NOT the same as background blur, as Bob Atkins mentioned in passing. DOF refers to the distance range within which the image is acceptably sharp. Background blur refers to the degree of blur in the areas that are not acceptably sharp. Background blur IS a function of focal length. Longer focal lengths give greater background blur if the subject-to-frame ratio is the same because of the narrower angle of view. (As the angle of view gets narrower, the background is expanded more to fill the frame, hence more blur.)

This is one of the main reasons (the other is reach) that some macro photographers prefer longer macro lenses. The greater background blur is appealing. Personally, shooting bugs with the narrower angle of view of an APS-C camera, I have found a 100mm lens fine and haven't gone for a more expense and heavier 150 or 180mm.

Until a few years ago, there was a superb post online by someone who used the name "toothwalker.org" that explained very clearly, with good photographic examples, the relationships between focal length and both DOF and background blur. Unfortunately, he took it down 8 years ago, and while he wrote to someone that he would put up a revised website, I haven't found it.

 

[Archibald]

... shooting pics with the same framing, DOF is the same regardless of lens focal length.

... If you move yourself so that the framing is identical, DOF is pretty much the same.

It ain't true until you have said it yourself.