SENSOR SIZE vs. DEPTH OF FIELD ??

[George D.]

All things being equal;

Same lens, same focus point, same f-stop, same ISO, etc.

Will a smaller sensor result in a larger depth of field than a bigger sensor?

Will the 2K portion of the RED-One sensor give a better depth of field than the full 4K size?

I ask this, because I need the “absolute maximum” depth of field I can get with my lenses, especially macro. I try my best to achieve between f16 - f32. For my kind of work, sensor size is not as important as depth of field.

Thanks.

 

[Subhadip Sen]

No, but the field of view will be much restricted. So, a wide shot at 4K will look like a medium or close-up at 2K.

One way to get a maximum depth of field is using the widest lens possible (i.e. lowest focal length). 2K means the image circle is much lesser. Perhaps a fish-eye 10mm (at 4K) would be a good standard wide at 2K (with no distortion due to the smaller image circle). Using a 10mm instead of (let's say) a 32mm will give you that extra depth of field, while keeping field of view the same (vs. 32mm at 4K). You should also dial up your ISO and go for the smallest aperture possible, shoot on a sunny day if EXT., or flood your set with lights if INT, etc. f/16 at 4K should give you a decent depth of field though.

 

[David Mullen ASC]

No, not if you don't change focal length to maintain field of view at the same distance when switching from 4K to 2K. If switching from 4K to 2K causes you to switch from a 100mm to a 50mm to get the same field of view, then yes.

Think of it this way, if you merely switch from 4K to 2K without changing anything else, it's still the same 4K image either way, just that it's been cropped in half in all directions to get a 2K image. But other than the loss of view, the content is the same.

In fact, technically there would be a loss of depth of field once you magnified the 2K image to become 4K again because you'd have to use a more critical Circle of Confusion figure at 2K to compensate for the degree of enlargement.

 

[Stephen Williams]

Working between F16-32 will produce softer images with a 4k sensor due to diffraction, going past F8/11 is a bad idea. With a 2/3" sensor I would not past F5.6.

At 1:1 even F16 will get you negligible DOF well under 1/2"

FWIW I shoot a huge amount of macro on 35mm film, I usually work in the F2-F4 range, I like to work with the narrow depth of field, it looks great.

 

[Stephen Williams]

One way to get a maximum depth of field is using the widest lens possible (i.e. lowest focal length)..

Depth of field will be identical with the same magnification, lighting will be more difficult using wide lenses. I am shooting an Omega Commercial next week, I will probably use a 24mm lens, the watch will average less than an inch from the front element.... I have 2 days for 3 shots so it's not an issue. If I need to work faster I would use a 50 or 85mm lens, however movement is so much cooler with wide lenses if you have the time. I will probably light to a F2.8 using dedolights.

 

[Subhadip Sen]

Depth of field will be identical with the same magnification, lighting will be more difficult using wide lenses. I am shooting an Omega Commercial next week, I will probably use a 24mm lens, the watch will average less than an inch from the front element.... I have 2 days for 3 shots so it's not an issue. If I need to work faster I would use a 50 or 85mm lens, however movement is so much cooler with wide lenses if you have the time. I will probably light to a F2.8 using dedolights.

What I meant was, using a ~10mm lens at 2K vs. ~30mm lens at 4K. You maintain the same field of view, but get a greater (deeper) depth of field. Basically the same as David mentioned.

 

[David Mullen ASC]

Now obviously if you are doing macro photography, the smaller sensor would allow you to use shorter focal lengths, with more depth of field, or the same focal length with more magnification. So there is an advantage. But the way the question was worded, no, you don't gain depth of field merely by switching from 4K to 2K if you don't change anything else.

 

[Michael Lindsay]

I am shooting an Omega Commercial next week, I will probably use a 24mm lens, the watch will average less than an inch from the front element.... ... movement is so much cooler with wide lenses if you have the time.

Giving away secrets!

A wider angle macro world is so often far more gripping and arresting.

Michael L

 

[Stephen Williams]

Interestingly I recently shot a Rolex watch with a 2/3 inch Video camera, the producer organised a 120mm Optex Macro (Leica) lens, it was the easiest lens to light for that I ever used. I would recommend people to use long lenses for macro, unless they have a great deal of time available.

 

[Stephen Williams]

Giving away secrets!

A wider angle macro world is so often far more gripping and arresting.

Michael L

Not really, most people don't have the patients to go down that route, unless using motion control lighting is probably impossible unless you just want flat & bright. I have shot watches that have had 30 passes of 35mm, different lighting for watch case, strap, face, diamonds, highlights etc all lighting multi exposure for HDR ....

 

[George D.]

Again, I guess I did not phrase my question correctly. So, let me put it another way:

If I shoot a subject 2 feet away with a 100mm lens at f16 on a 2K sensor, will it give me a "different" depth of field than shooting the same subject 2 feet away, using the same 100mm lens at f16 on a 4K sensor?

I realize the field of view will be different with each sensor size, but it's whether there is a difference in the depth of field I'm interested in knowing. The subject on the 2K sensor will of course look closer, than on the 4K sensor, because it's using only half the sensor's overall size. I understand that too.

I hope I made that clearer. Thanks.

 

[Joel Jameson]

Again, I guess I did not phrase my question correctly. So, let me put it another way:

Check out Mitch's explanation:
http://www.reduser.net/forum/showthread.php?t=45144

 

[Subhadip Sen]

If I shoot a subject 2 feet away with a 100mm lens at f16 on a 2K sensor, will it give me a "different" depth of field than shooting the same subject 2 feet away, using the same 100mm lens at f16 on a 4K sensor?

In that case, the simple answer is "No". The depth of field will remain the same.

 

[David Mullen ASC]

No, it's the same image just cropped in half in the horizontal and vertical directions, so depth of field hasn't changed. However, that cropped-to-2K shot will look deeper in focus compared to a 4K shot where you switched to twice as long a focal length or moved the camera twice as close to get the same field of view.

 

[D Fuller]

Interestingly I recently shot a Rolex watch with a 2/3 inch Video camera, the producer organised a 120mm Optex Macro (Leica) lens, it was the easiest lens to light for that I ever used. I would recommend people to use long lenses for macro, unless they have a great deal of time available.

Why? This is fascinating to me. Why is it more difficult to light for the wider lens?

 

[George D.]

No, it's the same image just cropped in half in the horizontal and vertical directions, so depth of field hasn't changed. However, that cropped-to-2K shot will look deeper in focus compared to a 4K shot where you switched to twice as long a focal length or moved the camera twice as close to get the same field of view.

Very, very interesting David.

So, if I understand you correctly, you're saying that I could get a BETTER "depth of focus" with a RED-One set on 2K, than I could with a Scarlet at 3K utilizing the SAME field of view. Is that true?

 

[David Mullen ASC]

If you are matching distance, f-stop, and field of view, then you'd have more depth of field at 2K instead of 3K because you'd have to use a longer focal length lens at 3K to match the field of view at 2K. Though in practical terms, it's probably about a 1-stop difference in depth of field characteristics due to the change in focal length.

What really affects depth of field is the distance, focal length, f-stop, and Circle of Confusion figure -- what field of view you get is merely the result of that focal length on that size sensor. But since you pick a lens based on the field of view you need, then that's why smaller sensors lead to more depth of field, because they cause you to switch to shorter focal lengths to get the same field of view you had on the larger sensor.

 

[Subhadip Sen]

Very, very interesting David.

So, if I understand you correctly, you're saying that I could get a BETTER "depth of focus" with a RED-One set on 2K, than I could with a Scarlet at 3K utilizing the SAME field of view. Is that true?

Isn't Red One 2K sensor-crop just slightly larger than the Scarlet 3K sensor? I may be wrong here, but I think if that were the case, Red One 2K will have slightly less depth of field. I.e., slightly shallower; and Scarlet 3K will be slightly more. Either way, Red One 2K crop is similar in size to Scarlet 2/3" 3K, so the depth of field will be very similar - if everything else matched.

Of course, Red One 3K will have lesser depth of field, compared to Red One 2K.

 

[George D.]

If you are matching distance, f-stop, and field of view, then you'd have more depth of field at 2K instead of 3K because you'd have to use a longer focal length lens at 3K to match the field of view at 2K. Though in practical terms, it's probably about a 1-stop difference in depth of field characteristics due to the change in focal length.

What really affects depth of field is the distance, focal length, f-stop, and Circle of Confusion figure -- what field of view you get is merely the result of that focal length on that size sensor. But since you pick a lens based on the field of view you need, then that's why smaller sensors lead to more depth of field, because they cause you to switch to shorter focal lengths to get the same field of view you had on the larger sensor.

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Thank you very much David.

I completely understand all that you've said, and it has been my experience as well dealing with 16mm and 35mm film cameras and lenses. What you've said also holds true for the differences between 8mm, 16mm, 35mm, and 70mm cameras and lenses.

I was only asking because I had "read" somewhere that smaller sensors, in and of themselves, produced larger depth of fields, which didn't make much sense to me, but I just wanted to verify it with someone like you, that REALLY knows what they are talking about.

Thanks again, and have a good one.

 

[David Mullen ASC]

Yes, I'm talking about 4K, 3K, and 2K on the same Red camera, not comparing the 3K 2/3" Scarlet to 2K cropped mode on the Red One, though they are probably in a similar size range, roughly in that 10mm width area.