How many f/stops to you use? How many do you need?

ThatCanonGuy

[FONT=Verdana, Arial, Helvetica, sans-serif]I was reading this article on Thom Hogan's site, bythom.com, a while ago. It's now on his 2011 archives page. Personally, I do like them how they are now. That's probably because I have to stay at about 1250 ISO or under on my 1DII. If I had access to clean ISO at 12800, I might rethink. But for now, I want access to all the apertures 1/3 stop apart. What do you think?[/FONT]

[FONT=Verdana, Arial, Helvetica, sans-serif][FONT=Verdana, Arial, Helvetica, sans-serif]RIP Apertures[/FONT]
[FONT=Verdana, Arial, Helvetica, sans-serif]Mar 22 (news)--[/FONT]Get ready for a wild ride. Ready? Really ready? Okay, you said you were ready: do we still need a set of 28 apertures all neatly spread 1/3 of a stop apart?
I'll wait a moment for those of you with pace makers to be revived.
I started pondering that question when I began using an APS sensor camera that had only two apertures. At first I wondered where the rest of them were, and then I thought about why I wanted them. Oops. Too much thinking gets me in trouble, doesn't it? Can't help it. I'm just wired that way, much to the chagrin of far too many former girlfriends.
In the film days, we used a roll of film that was absolutely fixed in sensitivity to light. While there were times when a few of us changed ISO rating mid-roll (and suffered a lot of pain and agony in doing so), most people never did that. Ever. So we needed both apertures and shutter speeds to change exposure. Sometimes you needed to fix one (shutter speeds for motion), sometimes you needed to fix the other (apertures for depth of field). Whatever you set, the other needed to balance to get a proper exposure.
But realistically, once exposure automation came along how often were we camera users setting intermediary settings? Not much. With apertures most photographers had three choices they made: wide open for low light, two stops down for sharpest results, and some small aperture (but not too small because of diffraction) for maximum depth of field. Yeah, all those charts in all those books (including mine) that gave you page after page of depth of field numbers were mostly wasted. For any given fixed focal length lens, most people only needed three small sets of numbers. Indeed, I memorized them.
The real reason why we had so many intermediary apertures was because of shutter priority. If the ISO was fixed and we needed 1/500 to stop motion, then the light would give us an arbitrary aperture opening we needed, and if we wanted exposure to be "accurate," we wanted a lot of small intermediary stops.
With me so far?
Is anything different today?
Yes. We can vary ISO. Most of us digital pros are still only using three apertures we set directly in aperture priority exposure mode (wide open, sharpest, and diffraction limit). But now both shutter speed and ISO can be moved to get the proper exposure. Likewise, if you shoot shutter priority, you can move the ISO. And with cameras like the D3s, I don't mind moving the ISO.
So this camera I was playing with was about to get a negative reaction from me for having only two apertures when I realized something: it had a built-in ND filter capability, plus it allowed me to set what were basically the wide open aperture or the diffraction limit aperture. Wide open the lens looked pretty darned sharp. So what did I need all the in between apertures for? Well, I didn't. And I don't miss them. Indeed, I get from one type of setting (low light) to the other (maximum DOF) with barely a flick. I'll be darned.
Legacy designs sometimes carry over useful things, and sometimes they just retain things that have lost some of their usefulness. If you think about it long enough, you're realize that we may not need all the apertures we've been hoarding all these years (1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22 and 18 other intermediary ones). But it's not a trivial process dropping them all, as there are consequences of messing with ISO and we do need NDs in the camera to help finesse that problem. Still, I'm not missing the missing apertures on this particular camera. Huh. Whodda thunk it?
Shh! Don't tell this to Apple! This is the kind of thing they like to discover and then disrupt an industry with. Oh dear, the Apple iStill, with Low-Light, Sharpest, and Deep Focus "apertures" only. Yeah, that'll confuse the mass market consumer ;~).
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I'm curious to know the thoughts of other Dgrinners.[/FONT]

Zerodog

Sometimes I think he is a weirdo. Most of the time his reviews just don't really fit my style. His shooting is so different than anything I do I need to take things with a grain of salt. To me aperture is DOF control. Straight up, that is it. I am an ISO shifter in this respect. I pick what DOF I want then set my shutter speed and ISO to make that happen.

lanaer

I suppose many photographers would use only a certain set of apertures to fit their style, but that set is likely going to be different for each photographer, so removing aperture options from lenses would mean they'd need multiple versions of lenses to serve different photographers...

Just doesn't seem worth it.

colourbox

I have read that for video, you want to shoot at specific ISO settings; I think Vincent LaForet says on Canons you should shoot video at ISO multiples of 160. Is any of that true for stills as well, for Canon or Nikon? Is it best to shoot at specific ISO increments? Because if it is, we don't have nearly as much flexibility with ISO as Hogan says, and we would still need our f-stops to do the fine tuning.

ThatCanonGuy

While I know zero about video, I don't think so with stills. Obviously lower is usually better when possible, but I don't think there are any specific magic numbers for stills.

Icebear

In theory I have little disagreement with this idea, but for me, with my Nikons, it sure is easier to change aperture on the fly than ISO. So like many things in life, the theory gets shunted aside in many practical applications.

ziggy53

colourbox wrote: »

I have read that for video, you want to shoot at specific ISO settings; I think Vincent LaForet says on Canons you should shoot video at ISO multiples of 160. Is any of that true for stills as well, for Canon or Nikon? Is it best to shoot at specific ISO increments? Because if it is, we don't have nearly as much flexibility with ISO as Hogan says, and we would still need our f-stops to do the fine tuning.

ThatCanonGuy wrote: »

While I know zero about video, I don't think so with stills. Obviously lower is usually better when possible, but I don't think there are any specific magic numbers for stills.

If all ISO sensitivities were generated in the same way there would not be any problem using "native" ISOs versus "fractional" ISOs.

Unfortunately it would appear that native ISOs are those produced by the imager, low noise amplifiers and calibrated tables in the image processor, and that the fractional ISOs are the native ISOs with additional gain applied. The reason people believe this is the case is by measuring the random noise levels at all available ISO settings:

http://www.northlight-images.co.uk/article_pages/cameras/canon_1ds3_noise.html

http://canonphotogroup.com/misc/test1.png

Native ISOs are not necessarily traditional base ISOs of 100, 200, 400, etc. Indeed there is no manufacturer published data of native ISOs. You should use a technique similar to that described in the Northlight link to determine your camera's native ISOs, if it is a concern.

Also see some fractional ISO video tests:

5D MKII:

http://vimeo.com/20239453

7D:

http://vimeo.com/​10473734