Macro Photos Without Focus Stacking.

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AeroPhotographer Forum Member • Posts: 87
Macro Photos Without Focus Stacking.

This article has example macro photos which are stacks of 20 exposures at f8.

https://www.dpreview.com/samples/9563106126/sample-gallery-macro-photos-with-a-motorized-slider?utm_source=self-desktop&utm_medium=marquee&utm_campaign=traffic_source

I got sharper results with a single exposure at f18.  I used the 18-135 kit lens on my A6400.  The key to depth of field is greater distance because depth increases with distance squared.  Here are pics.  Left is the stack of 20 frames, right is my single exposure.

Left is stack of 20 frames at f8.  Right is single exposure at f18

moficera Regular Member • Posts: 492
Re: Macro Photos Without Focus Stacking.
2

How does your technique work at 1:1 magnification?

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OP AeroPhotographer Forum Member • Posts: 87
Re: Macro Photos Without Focus Stacking.

moficera wrote:

How does your technique work at 1:1 magnification?

My tip is to increase the distance to the subject, then crop the image as desired. That's not feasible with 1:1. So try 1 to 0.2, then crop.  Also, I shot the example images with a normal lens which can't shoot closer than 1 to 0.3.

The depth of field increases with distance squared.  That's why it helps to increase the distance to the subject.

moficera Regular Member • Posts: 492
Re: Macro Photos Without Focus Stacking.
2

It was more a rhetorical question as I think an extreme crop is no substitution for real macro work. It might work for your examples but I would call them rather closeups.

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ZilverHaylide Contributing Member • Posts: 669
Re: Macro Photos Without Focus Stacking.
3

I applaud the OP's desire to hypothesize an alternative technique and experimentally test it, but there's more work to be done, more things to consider, before the conclusion would be valid and technique useful.

What's not being addressed by the technique is how many pixels the subject occupies, and how much resolution results, at the final magnification/print/display size.

Looking at it first from the perspective of number of pixels, the "gold standard" for a top-quality print is 300-360 pixels per inch. So if one backs off on the distance so that magnification ratio is 1:5 rather than 1:1, and the item of interest now occupies (at most) only 1/5 of the linear dimension of the frame, then even on a A7Riv, it now only takes up 9504 ÷ 5 = 1900 pixels. Printed at 300 ppi, that's a print with a long dimension of only 6.34 inches.

Similarly, looking at it from the resolution perspective, an optical system (lens and sensor) has (at any magnification ratio and MTF threshold) a maximum resolution in line-pairs per millimeter. If, because one has backed off, the subject now occupies only one-fifth of the linear dimension on the sensor it would have occupied if photographed closer, then it probably spans fewer line-pairs of result. (Unlike number of pixels, this isn't a straight-forward calculation, because lens resolution will vary at different magnifications and will depend on what the lens is optimized for. But even using lenses optimized for each of those magnifications, I believe that the number of line-pairs spanning the subject photographed will almost certainly be significantly lower if one reduces on-sensor magnification by a factor of 5.)

For a proper comparison against focus stacking, we would also need to know (either theoretically or experimentally) how much resolution may be lost via the stacking process, which I don't know, and the OP hasn't given any indication that he/she knows either.

There's no free lunch.

OP AeroPhotographer Forum Member • Posts: 87
Re: Macro Photos Without Focus Stacking.

I downsized my comparison pics to have the exact number of pixels that the author published. The watch face was 600x366 pixels. That was a factor of 5.08 smaller than my original 1860 pixels tall. Here it is.

I could easily double this pic in a quality upsizer. But it's already too tall for my intended

use, which is to be viewed online. I was not recommending my approach for gold standard prints. Incidentally the above pic is 46% of the full height of the frame.

Best regards,

Alan

PS  I just quickly composed the above pic and shot.  With a bit of experimenting and a smaller aperture, I can make a taller pic which is as sharp as the 20 frame stack.  Many photographers are afraid of small apertures due to diffraction.  But I recover diffraction softening with a bit of sharpening in edit.  Diffraction isn't nearly as severe as many people think it is.

ZilverHaylide Contributing Member • Posts: 669
Re: Macro Photos Without Focus Stacking.

AeroPhotographer wrote:

I downsized my comparison pics to have the exact number of pixels that the author published. The watch face was 600x366 pixels. That was a factor of 5.08 smaller than my original 1860 pixels tall. Here it is.

I could easily double this pic in a quality upsizer. But it's already too tall for my intended

use, which is to be viewed online. I was not recommending my approach for gold standard prints. Incidentally the above pic is 46% of the full height of the frame.

Best regards,

Alan

PS I just quickly composed the above pic and shot. With a bit of experimenting and a smaller aperture, I can make a taller pic which is as sharp as the 20 frame stack. Many photographers are afraid of small apertures due to diffraction. But I recover diffraction softening with a bit of sharpening in edit. Diffraction isn't nearly as severe as many people think it is.

I agree that your technique of just using a small aperture (and greater distance) looks fine if your use doesn't require too many pixels, or too much resolution. And online use (or small printed size) would certainly fall into that category.

Reducing subject size on sensor, you're effectively using a smaller format sensor, with the greater depth of field that provides. One could ACTUALLY USE a smaller sensor -- I've seen some nice close-up and macro results from some small-sensor Panasonic "bridge"-type cameras.

As with any photography, consideration of specific end-use is important in deciding what equipment and what technique makes sense in terms of adequate quality and cost- and time-effectiveness. Way too many persons on these forums spend an inordinate amount of time and money seeking a "better" -- or even the "best" -- camera or lens, without giving any significant thought about whether what they already have is actually more than good enough for their intended use.

This reminds me of a small rounded box-like device that my father had dating from the late 1940s or early 1950s for exposing enlarging paper to produce small black and white prints (perhaps 3.5 x 5 inches, for proofing, or even final results for uncritical use). Distances from negative and to paper were fixed, and it used a fixed-focus lens of very small size with what must have been a very small aperture (IIRC, about the size of a pinhead) to ensure adequate depth of field. Since use was B&W printing and paper sensitivity was relatively narrow band, chromatic aberrations were inconsequential and lens could be simple. No focusing was necessary, and small prints could be produced at a fairly fast pace and with little effort. Crude, but adequate and efficient.

BGD300V1
BGD300V1 Senior Member • Posts: 2,489
Looking at it from the numberer of pixels, I don't see a difference

If I fill the frame with a watch with a coin with a 24mm diameter which has a 2.4mm currency symbol we have a fixed image.

It doesn't matter if it was taken from 4 inches with a 60mm Macro lens, 7 inches with a 105 Macro lens or 5 feet with a 400mm telephoto.

The pixels used on the sensor are the same.

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moficera Regular Member • Posts: 492
Re: Looking at it from the numberer of pixels, I don't see a difference
1

You have to show the 400 mm telephoto lens that does 1:1 at 1.5 m.

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ZilverHaylide Contributing Member • Posts: 669
Re: Looking at it from the numberer of pixels, I don't see a difference
1

BGD300V1 wrote:

If I fill the frame with a watch with a coin with a 24mm diameter which has a 2.4mm currency symbol we have a fixed image.

It doesn't matter if it was taken from 4 inches with a 60mm Macro lens, 7 inches with a 105 Macro lens or 5 feet with a 400mm telephoto.

The pixels used on the sensor are the same.

Your suggestion of getting the same number of pixels via a stronger telephoto doesn't address the OP's issue and technique. He (or she) is trying to avoid stacking by increasing depth of field, partially by using smaller apertures and partially by backing away, shooting at a lower reproduction ratio -- so NOT filling the frame, and fewer pixels are unavoidable. I don't have a table of depth of field formulas in front of me, but I don't see any way around that. (And IIRC, you can't get around that by your suggestion of switching to a stronger telephoto, what matters is reproduction ratio. A stronger telephoto proportionally magnifies the out-of-focus circles of confusion, so you're back to where you started, you don't gain depth of field. Whereas a smaller reproduction ratio is like moving to M43 or a yet-smaller sensor, which is widely understood to increase depth of field).

BGD300V1
BGD300V1 Senior Member • Posts: 2,489
Re: Looking at it from the numberer of pixels, I don't see a difference

moficera wrote:

You have to show the 400 mm telephoto lens that does 1:1 at 1.5 m.

The FLs and distances were hypothetical.  I'm sure I could do something with extension tubes or teleconverters or a really long focus rail.

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BGD300V1
BGD300V1 Senior Member • Posts: 2,489
Re: Looking at it from the numberer of pixels, I don't see a difference
1

ZilverHaylide wrote:

BGD300V1 wrote:

If I fill the frame with a watch with a coin with a 24mm diameter which has a 2.4mm currency symbol we have a fixed image.

It doesn't matter if it was taken from 4 inches with a 60mm Macro lens, 7 inches with a 105 Macro lens or 5 feet with a 400mm telephoto.

The pixels used on the sensor are the same.

Your suggestion of getting the same number of pixels via a stronger telephoto doesn't address the OP's issue and technique. He (or she) is trying to avoid stacking by increasing depth of field, partially by using smaller apertures and partially by backing away, shooting at a lower reproduction ratio -- so NOT filling the frame, and fewer pixels are unavoidable. I don't have a table of depth of field formulas in front of me, but I don't see any way around that. (And IIRC, you can't get around that by your suggestion of switching to a stronger telephoto, what matters is reproduction ratio. (A stronger telephoto proportionally magnifies the out-of-focus circles of confusion, so you're back to where you started, you don't gain depth of field)).

For the purposes of the OP, quantifying magnification is pointless.  DOF it the primary consideration in a product shot.

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moficera Regular Member • Posts: 492
Re: Looking at it from the numberer of pixels, I don't see a difference

BGD300V1 wrote:

moficera wrote:

You have to show the 400 mm telephoto lens that does 1:1 at 1.5 m.

The FLs and distances were hypothetical. I'm sure I could do something with extension tubes or teleconverters or a really long focus rail.

Ok, that extension would have to be really long. Maybe the macro lens distances matched coincidentally.

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ZilverHaylide Contributing Member • Posts: 669
Re: Looking at it from the numberer of pixels, I don't see a difference

BGD300V1 wrote:

ZilverHaylide wrote:

BGD300V1 wrote:

If I fill the frame with a watch with a coin with a 24mm diameter which has a 2.4mm currency symbol we have a fixed image.

It doesn't matter if it was taken from 4 inches with a 60mm Macro lens, 7 inches with a 105 Macro lens or 5 feet with a 400mm telephoto.

The pixels used on the sensor are the same.

Your suggestion of getting the same number of pixels via a stronger telephoto doesn't address the OP's issue and technique. He (or she) is trying to avoid stacking by increasing depth of field, partially by using smaller apertures and partially by backing away, shooting at a lower reproduction ratio -- so NOT filling the frame, and fewer pixels are unavoidable. I don't have a table of depth of field formulas in front of me, but I don't see any way around that. (And IIRC, you can't get around that by your suggestion of switching to a stronger telephoto, what matters is reproduction ratio. (A stronger telephoto proportionally magnifies the out-of-focus circles of confusion, so you're back to where you started, you don't gain depth of field)).

For the purposes of the OP, quantifying magnification is pointless. DOF it the primary consideration in a product shot.

It is, but that's my point. You get some DoF gain by stopping down, but you often can't get the desired increased depth of field without backing away and getting the lower on-sensor number of pixels that is the result. After backing away, you CANNOT then try to compensate for the extra distance by bumping up to a more-telephoto lens, and returning to a filled frame -- without undoing your DoF gain.

OP AeroPhotographer Forum Member • Posts: 87
Re: Looking at it from the numberer of pixels, I don't see a difference

The simplified formula for depth of field is:

Depth = f# x k x (distance / focal length)^2

Where k is a small number depending on the units of "Depth" and the acceptable blur diameter.

The basis for my suggestion is that Depth increases with distance squared.  So when you double distance, the Depth increases by a factor of four.

Dofmaster.com will solve the formula for you but the results will depart slightly from the formula due to their using a more complicated formula.

Alan

ZilverHaylide Contributing Member • Posts: 669
Re: Looking at it from the numberer of pixels, I don't see a difference

AeroPhotographer wrote:

The simplified formula for depth of field is:

Depth = f# x k x (distance / focal length)^2

Where k is a small number depending on the units of "Depth" and the acceptable blur diameter.

The basis for my suggestion is that Depth increases with distance squared. So when you double distance, the Depth increases by a factor of four.

Dofmaster.com will solve the formula for you but the results will depart slightly from the formula due to their using a more complicated formula.

Alan

So (to the extent this simplified formula is accurate), this shows clearly why one can't back up but then switch to a more-telephoto lens to compensate. A (for example) doubling of the distance would require a doubling of the focal length to return to the original magnification, but the two doublings would cancel each other out in the formula, resulting in no DOF increase. The only way to gain DOF is for the on-sensor image size to be smaller (lower effective magnification). The image must be small, meaning that on a large sensor, it will take up a small fraction of that sensor. On a smaller sensor, it can occupy a larger proportion of the sensor while still remaining the same small size.

Depending on pixel size on the two sensors, the item imaged might or might not span more pixels on the smaller sensor, more pixels potentially advantageous resolution-wise. The smaller pixels would likely have reduced dynamic range, but for a product photographed in a studio setting, lighting (or HDR) techniques should be able to keep dynamic range under control.

macrouser
macrouser Regular Member • Posts: 408
Re: Macro Photos Without Focus Stacking.

Even though most of my photos are done with macro lenses doesn't require me to always get a 1:1 ratio for the picture.  My subjects are often fast moving insects that will spook very easily.  If I can fill at least one square on a rule of thirds grid,  I will get a good picture.

The challenge is to get a good picture.  A macro lens helps me to do that.  Sometimes that means that I will back up to get more of the subject in focus.  The part of the picture in focus is more useful than the out of focus area.

At macro distance or very close focus,  chromatic diffraction is so small that you would need to enlarge the picture to an extreme size to detect it.  Even then, the areas in focus would look much better with less diffraction then the out of focus area.

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