1:1 at f/36 Versus 1:2 at F/8 Cropped

[WayneF]

If you prefer to trade in four stops of light for 2 micron fuzziness, what's there left to say?

Well, let's see... four stops could be f/40 vs f/10 (4 stops).

Let's see... This was f/11 (less than 4 stops)

Darn tooting! That looks like very much more than 2 microns to me. It is an "Inch" ruler with 105mm lens, macro distance.

Do you see the diffraction hurting this one? Where? <he he he>

Stopping down obviously can often improve the overall picture, when the DOF helps more than the diffraction hurts. If it helps, it helps.
I've known that for decades, and it is much older knowledge.

From Diffraction limited images? Really?

 

[J-see]

Flabbergasted is the correct term I believe.

I'll call it quits if I even have to explain what the four stops of light applies to.

Btw, it's amazing how you took two shots at different aperture but identical distance and got two different DoF. I tip my hat to such craftsmanship.

 

[WayneF]

Flabbergasted is the correct term I believe.

I'll call it quits if I even have to explain what the four stops of light applies to.

To me, it meant I had supply 16 times more light. No big deal, one simple speedlight. Don't recall, it was not noteworthy, but maybe 1/2 power instead of 1/32 power (macro is at only a few inches).

Btw, it's amazing how you took two shots at different aperture but identical distance and got two different DoF. I tip my hat to such craftsmanship.

Really? It is such a basic principle, and you've never heard of stopping down improving DOF? Really?
Maybe you're just making a joke, but the rest of your DOF discussions suggest flabbergasted is the word.

 

[Woodyg3]

J-see, he's asking if diffraction is causing IQ problems in the f/40 shot. Note that the f/40 shot is pretty sharp, and that there is a great deal of DOF compared to the f/11 shot.

Now, if you are still clinging to the belief that you can get the same depth of field by shooting with a larger aperture further away from the subject, WITH THE OBJECTS AT THE SAME IMAGE SIZE (which, by the way, would be MAGNIFICATION) you are simply mis-understanding depth of field. Honest.

 

[J-see]

I might be mistaken but the rest of us here was informed that one has to adjust magnification at the same time if one wants to maintain the same DoF.

I said it plenty of times and it's even in the title of this post but maybe we need to use a LARGER FONT.

 

[J-see]

J-see, he's asking if diffraction is causing IQ problems in the f/40 shot. Note that the f/40 shot is pretty sharp, and that there is a great deal of DOF compared to the f/11 shot.

Now, if you are still clinging to the belief that you can get the same depth of field, WITH THE OBJECTS AT THE SAME IMAGE SIZE (which, by the way, would be MAGNIFICATION) you are simply mis-understanding depth of field.

He's taking two identical shots using different aperture at the same magnification. It would only be a wonder if the DoF would not be different.

Whether or not diffraction hurts is of no relevance to what we are talking about here. Apples and oranges.

 

[Woodyg3]

He's taking two identical shots using different aperture at the same magnification. It would only be a wonder if the DoF would not be different.

Right, but do you see an IQ problem with the f/40 shot?

And, again, you can't get the DOF shown in this f/40 shot by shooting farther away with the same lens and opening up the aperture. You will have to crop the resulting image to make objects the same size, and the cropped photo will have shallower depth of field. Look at your first to sample shots for proof.

Anyway, I look forward to seeing more of your dog and bird pictures. Have you done any long exposure night shots lately? Those were fun to see.

 

[J-see]

Let's check the sharp part in a 100% crop and we can talk about IQ issues. I can show you shots that look nice at web-format and contain no sharp detail at 100%.

Of course you can get the same DoF. Closing up enlarges the DoF, opening shrinks it, magnifying more shrinks it while magnifying less enlarges it again. Those two can be balanced against each other. That's what it is all about.

I got a bit tired of long exposure and at the moment I have a hard time not using the new lens. At some point she'll get some rest but at the moment she's too fantastic to resist.

 

[Eyelight]

Something here I tried to point out a few posts (pages back). First, I'll reiterate that calculations get you to the ballpark, but then comes subjectivity.

Here is the formula for calculating close focus DOF using f/stop, magnification and CoC (same as shown on Wikipedia):



Here then are calculations using this formula for a DX:

f/stop	N	36	32	8
CoC	c	0.02	0.02	0.02
Magnification	m	1	1	0.5
	DOF	2.88	2.56	1.92

And for the FX:

f/stop	N	32	8
CoC	c	0.03	0.03
Magnification	m	1	0.5
	DOF	3.84	2.88

Using this formula, the calculated DOFs are not the same for 1:1 at f/32 and 1:2 at f/8.

 

[WayneF]

Let's check the sharp part in a 100% crop and we can talk about IQ issues. I can show you shots that look nice at web-format and contain no sharp detail at 100%.

OK... 100% crop, and you should be able to click them and see it a bit larger.
Should be obvious, but f/11 first, then f/40. Exif is in these, but I doubt the forum can show it, from external location.

These are even with a D800 with its little diffraction limited pixels. LOL That is hokum too. It's not about pixels.

Sure, f/40 diffraction has to be there, but who cares? Image quality is about the full frame of the image. 100% is rarely a real world application (not with 36 megapixels. ). But DOF can really help the real world full picture.

Of course you can get the same DoF. Closing up enlarges the DoF, opening shrinks it, magnifying more shrinks it while magnifying less enlarges it again. Those two can be balanced against each other. That's what it is all about.

I've never had a clue what your presentations have been about. It all seems wrong, making stuff up, makes no sense to me.

What it's about to me is that DOF is an extremely good thing, often better than diffraction is bad.

 

[mikew_RIP]

I will not say i find this thread interesting as i dont really,the conclusion i have come to though is confusion about the purpose of an image.From the point of view of a happy ignoramus if i was taking pictures of printed circuit boards then i may be concerned about diffraction, if i was taking pictures of the beauty of nature and unless the lens was extremely poor DOF is far more important than a bit of diffraction,i have never seen a comment on here thats a great picture of a bee fantastic DOF but the diffraction spoils it.
My two cents worth as they say and i will not be beaten by a reply and then not reply again its just some threads i tend to air my views then not post again,especially when i see no sensible conclusion being reached.

 

[J-see]

I've never had a clue what your presentations have been about. It all seems wrong, making stuff up, makes no sense to me.

What it's about to me is that DOF is an extremely good thing, often better than diffraction is bad.

Again; it is not about less DoF we are talking about. Maybe it would be good if you'd actually read the thread and what we are talking about and not only read the words diffraction and DoF.

The question here is; DoF being equal for both, would a lesser magnification that needs to be cropped have less image quality afterwards than a shot taken fully closed down? And if yes; how much of that quality is worth the four stops of light that can be invested elsewhere because we shoot wider open?

Btw, the crop you post to show IQ loss isn't really a crop. At 1:1 that's 1/2 my sensor.

 

[Scott Murray]

I am just wondering what the aim of this thread is!? What are you trying to prove?

 

[J-see]

I am just wondering what the aim of this thread is!? What are you trying to prove?

It's about wondering whether the one approach is a more sensible option than the other. I'm convinced it is. Eyelight maybe not as much and we're posting shots to show how we see it.

If others have their views upon the actual subject we talk about, let them feel free to jump in. If they don't care, let them feel free to ignore this thread.

 

[Scott Murray]

It's about wondering whether the one approach is a more sensible option than the other. I'm convinced it is. Eyelight maybe not as much and we're posting shots to show how we see it.

If others have their views upon the actual subject we talk about, let them feel free to jump in. If they don't care, let them feel free to ignore this thread.

The way I see it and have found out you will always get better result using all the sensor than cropping. I tend to avoid cropping even on my D800E.

 

[J-see]

The way I see it and have found out you will always get better result using all the sensor than cropping. I tend to avoid cropping even on my D800E.

That's the thing we wonder about and maybe it is depending upon sensor/lens.

I remember doing D3300-D750 comparisons where I cropped the D750 to get the same shot as the D3300 and the quality was not very different since what the D750 lost in pixels, it made up in sharpness.

I'm of the opinion the same is true when shooting macro with my cam/lens. My loss in pixels or my loss of sharpness will not be that dramatically different which makes cropping at the sharpest aperture for me the most sensible option since I can invest those stops of light aperture required into shutter speed.

 

[Eyelight]

For all who wonder, Post #8 is a fair summary of the why and the what of the thread. It's essentially a spin-off discussion brought here to minimize the impact on the former thread.

Again; it is not about less DoF we are talking about. Maybe it would be good if you'd actually read the thread and what we are talking about and not only read the words diffraction and DoF.

The question here is; DoF being equal for both, would a lesser magnification that needs to be cropped have less image quality afterwards than a shot taken fully closed down? And if yes; how much of that quality is worth the four stops of light that can be invested elsewhere because we shoot wider open?

Btw, the crop you post to show IQ loss isn't really a crop. At 1:1 that's 1/2 my sensor.

The DOF is not equal. When you first stated you could get better results at 1:2 and f/8 than you could at 1:1 and f/32, I thought you were throwing out an opinion. I did not realize until part way through this thread that you were basing your thoughts on the idea that the DOF of these two combinations was the same. They are not. I first mentioned the difference in post #22 and then provided calculations based on a formula you provided from Wiki P in Post #49. The flower images in Post #1 show this quite well and your bit images also show it very obvious in the two full shots in post #21, because if the DOF's were equal, then the blur in the 1:2 shot would actually appear less than the blur in the 1:1 shot.

The four stops of light I used to get to f/32 did not affect the shutter speed. Check the EXIF.

That's the thing we wonder about and maybe it is depending upon sensor/lens.

I remember doing D3300-D750 comparisons where I cropped the D750 to get the same shot as the D3300 and the quality was not very different since what the D750 lost in pixels, it made up in sharpness.

I'm of the opinion the same is true when shooting macro with my cam/lens. My loss in pixels or my loss of sharpness will not be that dramatically different which makes cropping at the sharpest aperture for me the most sensible option since I can invest those stops of light aperture required into shutter speed.

More blur being cast by the lens is more blur regardless of sensor. The D750 may possibly beat the D3300 using the crop, but the D750 cannot beat the D750 using the crop.

 

[J-see]

I simply can't believe the denial about DoF being identical. It's based upon the same principle as controlling the amount of light using aperture and shutter.

If aperture/magnification is impossible, it implies that when I have a certain amount of light using f/8 at 1/125s, it is simply impossible to get that same amount using any other setting.

I give up.

 

[Woodyg3]

I will not say i find this thread interesting as i dont really,the conclusion i have come to though is confusion about the purpose of an image.From the point of view of a happy ignoramus if i was taking pictures of printed circuit boards then i may be concerned about diffraction, if i was taking pictures of the beauty of nature and unless the lens was extremely poor DOF is far more important than a bit of diffraction,i have never seen a comment on here thats a great picture of a bee fantastic DOF but the diffraction spoils it.
My two cents worth as they say and i will not be beaten by a reply and then not reply again its just some threads i tend to air my views then not post again,especially when i see no sensible conclusion being reached.

LOL. I agree that this isn't all that interesting. I just don't want a beginning photographer to read this thread and get confused as to what depth of field is and how to use/control it. At this point, I would urge a new photographer to scrub their mind of what they have read in this thread and go read a basic primer on depth of field.

I also agree that I have yet to see a macro picture of a bee that was shot at a small aperture and "ruined" by diffraction. Quite the opposite, actually.

 

[WayneF]

The question here is; DoF being equal for both, would a lesser magnification that needs to be cropped have less image quality afterwards than a shot taken fully closed down? And if yes; how much of that quality is worth the four stops of light that can be invested elsewhere because we shoot wider open?

Absolutely less, for more than one reason. You miss the big picture. You heard stopping down increases diffraction, and that's all you can think about. I heard it increases DOF and improves the image, and that's proved very big with me.

Lesser magnification (including cropping which is a bit different)... but both must be enlarged more to show it the same viewing size. Enlargement is magnification, which enlarges CoC too, which reduces DOF. DoF is judged by how visible the enlarged and viewed CoC appears. This is why CoC definition is specified as a tiny percentage of the image diagonal (to be proportional to the standard enlargement that it is viewed at... standard so it can be compared). The Carl Zeiss formula is one of the most popular, and it arbitrarily specifies CoC to be (diagonal / 1730). DOF is only about magnification (when viewed). It all fits together well if you know a thing or two.

Zeiss formula - Wikipedia, the free encyclopedia

BTW, some whippersnapper on Wikipedia says 2001, but the Zeiss 1730 value was well known in the late 1950s. This stuff is ancient, it's been known forever.

FX CoC is often given as 0.03 mm. FX diagonal is 45.3 mm / Zeiss 1730 is 0.025mm CoC. But there are several other arbitrary guesses than Zeiss'. It's really just what is imagined visible to the eye at standard 8x10 enlargement (an approximation, but viewed at 10 inches). But there are more facts known than just the notions you make up.

CoC x total magnification is the diameter that becomes visible to us. That is its definition. Thinking people only compare it numerically under the same fixed viewing conditions. Back in the day, doing darkroom work, when we came across a good image, we made an 8x10. It is how we viewed it. Only way we had. Today, we don't print much, but 8x10 at 10 inches is still the standard where the CoC number is defined to be visible. Anything else is just ignorance of the facts. Great as the internet is, it has lost a lot, allowing any idiot to post any stupid thing.

2. and it is NOT equal DOF. DOF is magnification, longer lenses, or shorter distances, etc. Yes, one property can balance the other, and DOF is said equal if the subject object is still same size. But you word it less magnification, and a smaller image always has to be enlarged more, which enlarges CoC too, reducing DOF.

Four stops: If stopping down makes a considerable improvement in DOF, and certainly it can and usually does, if the proper situation (esp macro), then of course it is normally well worth it. Certainly to me it is.


I do understand this discussion is totally pointless. You never consider one detail that I say. You ignore all, and just say meaningless words back. Still, it's kinda fun (and funny), and I have the satisfaction of knowing I'm right (not just something I just made up), and it might influence others who actually think about the facts.

If aperture/magnification is impossible, it implies that when I have a certain amount of light using f/8 at 1/125s, it is simply impossible to get that same amount using any other setting.

You have really never heard of Equivalent Exposures? It is the basis of EV, a chart of multiple setting combinations for same exposure.