SENSOR SIZE vs. DEPTH OF FIELD ??

[Subhadip Sen]

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.

This is technically false, but indirectly true. Unless someone expressly claimed that small sensors have larger depth of field at the same focal lengths, which is false. However, at the same field of view, small sensors do have larger depth of field, so you can excuse someone for saying "small sensor = greater depth of field" as that is a valid observation, even though not technically accurate.

 

[George D.]

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.

I'm asking about all this, because I'm trying to make the decision if it would be better "for my purposes in doing Macro", to shoot with a RED-One in 2K or 3K, or a Scarlet in 3K.

It looks like to me, "ALL things" considered, it would be better to use the Scarlet than the RED-One.

 

[Jeff Kilgroe]

If it's a consideration of shooting 2K or 3K on the RED One, then I would probably steer you toward the 2/3" Scarlet. The 2K area recorded on the RED One is 11.06mm wide. On the Scarlet, you get 3072 pixels in a sensor area that's 10.14mm wide. If your aim is a smaller imager with shorter focal lengths, to increase your DOF, the 2/3" Scarlet may be the best choice for those parameters due to the high-density sensor.

David Mullen has done a great job, as usual, of explaining the sensor size vs. DOF. But I think there are other factors for you to consider besides sensor size alone. Resolution should always be a factor, as should your intended subjects, distances, framing, lens selection, what you are using now, etc..

 

[Stephen Williams]

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

There comes a point where the object touches the front element of the lens! Having 30cm plus of space makes life much easier, I usually end up working with 5-10cm (2-4 inches) between the object & front element of the lens.

The lens being closer will also be larger in reflections......It's basically down to how much the client wants to spend, 1 shot in 2 days or 1 shot per hour, take your pick or anything in between!

 

[jimhare]

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I was only asking because I had "read" somewhere that smaller sensors, in and of themselves, produced larger depth of fields

Yeah, this has been a hot topic for a couple of years now.

I have taken to a simplistic explanation:

The larger the sensor, the longer the lens you need for the same field of view.

Since longer lenses naturally have a shallower depth of field, this is why the same image (field of view) appears to have a shallower depth of field in larger sensor than a smaller one, when framing the same image.

So while the "effect" is real, it is not the sensor itself creating the change in DOF, it's the choice of lens. I believe this is what has caused the confusion.

This has been wonderfully demonstrated in Mitch's great video and should quell all doubts.

 

[Mitch Gross]

Link again to my video:

http://blog.abelcine.com/2010/05/14/a-lens-is-a-lens-is-a-lens/