P4P f-stop sweet spot?

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With my DSLR lens my 17-40 has the best focus around f11 (range f4-f22) but another lens is best at f9. Has anyone found the best f-stop for the p4p yet or is it generally the same thru out and switching f-stops is most useful to get your shutter (assuming no ND filters are available) as close to 2x the frame rate? Thank you.
 
For stills, f/5.6 seems to work well for me, in most cases. Play around with it, trial and error will normal give you the best results.


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I ran some tests and found f4 or f5.6 to be the spot..at higher f stops the edge of the frame was not as sharp.
 
With my DSLR lens my 17-40 has the best focus around f11 (range f4-f22) but another lens is best at f9. Has anyone found the best f-stop for the p4p yet or is it generally the same thru out and switching f-stops is most useful to get your shutter (assuming no ND filters are available) as close to 2x the frame rate? Thank you.

Not even on a full sized full frame DSLR is f/11 the sweet spot -- by that point diffraction will be reducing recorded resolution. I find that with my full frame DSLR's the sweet spot is more like f/6.3-f/8 but can be a lower f/# if the scene permits it. So, if I'm shooting from a high vantage point that has no close object in the FOV you are better off using more like f/4 or so for a couple reasons. First, at f/4 there is very little diffraction limiting and a faster shutter speed helps to reduce blurring due to subject or camera motion.

Here's a test you can do that will confirm what I say. Set you camera up on a tripod and take pictures in aperture priority mode of the same scene at f/4, f/5.6, f/6.3, f/7.1, f/8, f/9, f/10, f/11 and f/13. Then look at the file size for each image -- I think you'll see that your maximum file size will tend to be around f/6.3 to f/8 with f/7.1 often the max. What's happening here is that the raw image is being lossless compressed and the file size is larger when there is more recorded detail. A high f/# will increase DOF but at the cost of diffraction, a lower f/# will have less diffraction blurring but at the cost os lower DOF. In the middle is the sweet spot most of the time. But, if you can frame the shot without close object or if everything is at nearly the same distance than that moves the sweet spot to a lower f/# -- even down below f/4 under some circumstances. OTH, if you have a shot that has huge differences in DOF and you want as much in decent focus as possible than go ahead and shoot at f/11 or even higher. Just know that your image will not be recorded at full resolution -- physics won't permit it.

With the smaller sensors on the P4P and similar drones the sweet spot will be a lower f/#. For the P4P I'd put the sweet spot at more like f/4 to f/7.1.


Brian
 
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Probably between f4 and 5.6, principally due to the diffraction limit (small sensor with high pixel density).


So far, the video I shot that has the best detail was recorded at f/5.6. Another one shot at f/6.3 is also pretty good but probably not as good as the one at f/5.6.


Brian
 
So far, the video I shot that has the best detail was recorded at f/5.6. Another one shot at f/6.3 is also pretty good but probably not as good as the one at f/5.6.


Brian
The pixel size is, theoretically, 2.92 μm- it may differ from this given the micro lens structure and layout of the associated cmos electronics. On pure numbers you should expect diffraction to be apparent at f5.6 (for 100%crop). The effect may be partially averaged out in video mode given some interpolation must occur to arrive at the lower resolution and the codec will also have some effect here (compression).
 
The pixel size is, theoretically, 2.92 μm- it may differ from this given the micro lens structure and layout of the associated cmos electronics. On pure numbers you should expect diffraction to be apparent at f5.6 (for 100%crop). The effect may be partially averaged out in video mode given some interpolation must occur to arrive at the lower resolution and the codec will also have some effect here (compression).


You get some diffraction at even lower f/#'s but the effect is small less than f/4. Diffraction plays a role above that but so does the increase in DOF so there's a trade off. At about f/7.1 the benefit of increased DOF is more than offset by diffraction so that would be about as high as I would go. In my own testing, which was not particularly scientific, I found f/6.3 to be quite usable but f/5.6 was better.

One thing that needs to be mentioned is that the aerial perspective we get from a drone tends to limit the need for greater DOF so we can safely use a wider aperture. In my example with a full frame DSLR, in my case the Nikon D800E, I find f/7.1 to give about the greatest detail even though diffraction is already having an effect. You have to chart DOF and diffraction and the sweet spot tends to be someplace between them. If I were shooting from an aerial perch so that there were no close by objects then I'd tend to open up from f/7.1 to perhaps f/5.6 or even f/4 with my D800E. With the M43 and similar sensors the f/#'s needs to be a bit less.


Brian
 
You get some diffraction at even lower f/#'s but the effect is small less than f/4. Diffraction plays a role above that but so does the increase in DOF so there's a trade off. At about f/7.1 the benefit of increased DOF is more than offset by diffraction so that would be about as high as I would go. In my own testing, which was not particularly scientific, I found f/6.3 to be quite usable but f/5.6 was better.

One thing that needs to be mentioned is that the aerial perspective we get from a drone tends to limit the need for greater DOF so we can safely use a wider aperture. In my example with a full frame DSLR, in my case the Nikon D800E, I find f/7.1 to give about the greatest detail even though diffraction is already having an effect. You have to chart DOF and diffraction and the sweet spot tends to be someplace between them. If I were shooting from an aerial perch so that there were no close by objects then I'd tend to open up from f/7.1 to perhaps f/5.6 or even f/4 with my D800E. With the M43 and similar sensors the f/#'s needs to be a bit less.


Brian

I shoot at f0.87 on M43 and it's pretty sharp.
 
That's quite a lens you got there even for a M43 lens -- care to give us some more details on this lens.


Brian
I wasn't referring to an M43 lens. Metabones speedboostet adapter with Canon 50 and 85mm f1.2 (speedbooster gives effective focal length of 0.7 while increasing effective fstop by 1). And as an added bonus MFT is also improved. I do have Voigtlander m43l primes which are f/0.95 and nice and sharp.
 
I wasn't referring to an M43 lens. Metabones speedboostet adapter with Canon 50 and 85mm f1.2 (speedbooster gives effective focal length of 0.7 while increasing effective fstop by 1). And as an added bonus MFT is also improved. I do have Voigtlander m43l primes which are f/0.95 and nice and sharp.


Ah, got it. I know a lot of Indy film makers that use the GH4 with the Metabones and the Sigma 18-35. My kit of M43 lenses are certainly not in that category though I do have some nice glass for my Nikon's. The GH5, which may become available in April, looks to be a pretty amazing camera and should sell like hot cakes to the Indy folks.


Brian
 
Looking at the test series above (red brick building) I'd say f/6.3 is quite acceptable and only at f/8 does it become distractingly soft.

I don't care about the fatter end as most of my shooting will be deep.

Real issue is the shutter speed - ND's wot. Need more.
 
Not even on a full sized full frame DSLR is f/11 the sweet spot -- by that point diffraction will be reducing recorded resolution. I find that with my full frame DSLR's the sweet spot is more like f/6.3-f/8 but can be a lower f/# if the scene permits it. So, if I'm shooting from a high vantage point that has no close object in the FOV you are better off using more like f/4 or so for a couple reasons. First, at f/4 there is very little diffraction limiting and a faster shutter speed helps to reduce blurring due to subject or camera motion.

Here's a test you can do that will confirm what I say. Set you camera up on a tripod and take pictures in aperture priority mode of the same scene at f/4, f/5.6, f/6.3, f/7.1, f/8, f/9, f/10, f/11 and f/13. Then look at the file size for each image -- I think you'll see that your maximum file size will tend to be around f/6.3 to f/8 with f/7.1 often the max. What's happening here is that the raw image is being lossless compressed and the file size is larger when there is more recorded detail. A high f/# will increase DOF but at the cost of diffraction, a lower f/# will have less diffraction blurring but at the cost os lower DOF. In the middle is the sweet spot most of the time. But, if you can frame the shot without close object or if everything is at nearly the same distance than that moves the sweet spot to a lower f/# -- even down below f/4 under some circumstances. OTH, if you have a shot that has huge differences in DOF and you want as much in decent focus as possible than go ahead and shoot at f/11 or even higher. Just know that your image will not be recorded at full resolution -- physics won't permit it.

With the smaller sensors on the P4P and similar drones the sweet spot will be a lower f/#. For the P4P I'd put the sweet spot at more like f/4 to f/7.1.


Brian


You cannot state categorically that f/11 cannot be the sweet spot on a 35mm full frame lens. I shoot Canon 5Ds bodies and one of my favorite lenses is the Zuiko 35mm PC lens. It is absolutely sharper at f/11 than it is at f/8. I have tested it extensively.

The sweet spot is NOT just the smallest aperture one can use prior to diffraction becoming an issue. It is theoretically possible that a lens might have its sweet spot wide open. Highly unlikely, but it IS possible.
 
You cannot state categorically that f/11 cannot be the sweet spot on a 35mm full frame lens. I shoot Canon 5Ds bodies and one of my favorite lenses is the Zuiko 35mm PC lens. It is absolutely sharper at f/11 than it is at f/8. I have tested it extensively.

The sweet spot is NOT just the smallest aperture one can use prior to diffraction becoming an issue. It is theoretically possible that a lens might have its sweet spot wide open. Highly unlikely, but it IS possible.

No, f/11 is not the ideal setting for detail on a full frame DSLR and I'd argue the max detail is more like f/7.1. There are situations where going to f/11 or even higher is preferred and there are occasions where opening up to f/4 or even faster is preferred, but for most situations my experience with full frame DSLR says f/7.1 is the setting that results in the greatest detail. For a camera with a smaller sensor the f/# that achieves the greatest detail is more like f/5.6 or even lover. The really small sensors like a GoPro have a fixed aperture in the f/2.8 range and they tend to have just about everything in decent focus.


Brian
 
No, f/11 is not the ideal setting for detail on a full frame DSLR and I'd argue the max detail is more like f/7.1. There are situations where going to f/11 or even higher is preferred and there are occasions where opening up to f/4 or even faster is preferred, but for most situations my experience with full frame DSLR says f/7.1 is the setting that results in the greatest detail. For a camera with a smaller sensor the f/# that achieves the greatest detail is more like f/5.6 or even lover. The really small sensors like a GoPro have a fixed aperture in the f/2.8 range and they tend to have just about everything in decent focus.


Brian

There is NO ideal apterure for a DSLR that translates to all lenses. Your previous post made it sound as if there WAS such an f/stop. I have been a professional architectural photographer for 35 years. Each lens needs to be tested. Most WILL end up with the greatest detail being just under where diffraction starts to appear, but not all.

Rather than encouraging someone to just use f/7.1 as their go-to best aperture on a DSLR, why not encourage them to explore their own gear with a series of simple tests that will be tailored exactly to their lenses?

I will say this one more time - I have a lens for a full frame DSLR (Canon 5Ds is what I use it on) and it is far superior at f/11 than it is at f/8 and f/16. I have owned 4 of these lenses in fact. They have ALL found their best performance at f/11. I know someone who is perhaps one of the best architectural shooters in the world who I told about this lens. He bought one, tested it and... surprise surprise, he reports the sweet spot at a very obvious f/11 too.

Test your gear people. It is not as simple as you think it is. But it's not hard to find out the truth with just a few minutes of your time.
 
There is NO ideal apterure for a DSLR that translates to all lenses. Your previous post made it sound as if there WAS such an f/stop. I have been a professional architectural photographer for 35 years. Each lens needs to be tested. Most WILL end up with the greatest detail being just under where diffraction starts to appear, but not all.

Rather than encouraging someone to just use f/7.1 as their go-to best aperture on a DSLR, why not encourage them to explore their own gear with a series of simple tests that will be tailored exactly to their lenses?

I will say this one more time - I have a lens for a full frame DSLR (Canon 5Ds is what I use it on) and it is far superior at f/11 than it is at f/8 and f/16. I have owned 4 of these lenses in fact. They have ALL found their best performance at f/11. I know someone who is perhaps one of the best architectural shooters in the world who I told about this lens. He bought one, tested it and... surprise surprise, he reports the sweet spot at a very obvious f/11 too.

Test your gear people. It is not as simple as you think it is. But it's not hard to find out the truth with just a few minutes of your time.

As a photographer I don't do everything in the sharpest zone. Sometimes f/16 is right and **** the diffraction if it gives you the FG detail for a WA shot.

With these small drone cameras, though, a fairly large aperture (f/5.6 ish) gives more than enough DOF for the style of photography being done generally - nothing in the FG.
 
As a photographer I don't do everything in the sharpest zone. Sometimes f/16 is right and **** the diffraction if it gives you the FG detail for a WA shot.

With these small drone cameras, though, a fairly large aperture (f/5.6 ish) gives more than enough DOF for the style of photography being done generally - nothing in the FG.
And this is the point. Diffraction limit, available light, desired DOF, required shutter speed, ISO (acceptable grain/noise/dynamic range) are all very real constraints and we often find we will move away from the technically favoured f-stop as the best compromise in meeting the overall objective. A good example is macro photography- almost without exception you will end up with an f stop on the dark side of the theoretical diffraction limit (you may shoot at higher ISO also) where the increased apparent depth of apparent sharpness is the preferred objective (you don't always have the luxury of focus stacking to get the shot). I often find that those who obsess with pixel level assesment of their work don't produce many images that truly move people.
 

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