Digital Cameras depth of view

[The PIT]

Is it my imagination or are the apperature ranges getting smaller these days.

For example Fujifine pix S602 ranges to 2.8 - 11 Fujifine pix S7000 2.8 - 8.

I looked at other cameras at the number eight seems the magical number.

[Wulfman]

well, hard to say if that is a good thing: is the "biggest" number the maximum aperture for that lens or the minimum aperture at the longest focal lenght?

mfg
wulfman

[The PIT]

Would be nice to have the option though on the more expensive cameras. Dunno why they removed from the S7000.

Got to admit sometimes though, outdoors it can be so gloomy that the only apature size I can use is 2.8. Otherwise the dreaded camera shake warning comes up. I suppose I can take a tripod and a few floodlights around with me.

[SpiralDragon]

heh..... a few HMIs ought to do the trick...

[spadnos]

Originally posted by Wulfman
well, hard to say if that is a good thing: is the "biggest" number the maximum aperture for that lens or the minimum aperture at the longest focal lenght?

mfg
wulfman

Looking at the photos on DP Review and Steve's Digicams (no relation), it looks like the lens is actually f2.8-3.1 over the zoom range. The DP Review feature chart shows f2.8-8 with 10 steps, which corresponds to 1/3 stop increments.

It sounds pretty stupid to me to reduce the aperture range, but it may make sense for their market. A "pro" photographer (who actually knows and cares about depth of field) would buy a more expensive camera. If you give a "consumer" a camera that they can set to f22, they have to have a tripod or flash to get a good picture, and will blame the camera when their shots are blurry from their hand shake (the opposite of deep depth of field )

- Steve

[az]

This might be the case on Fuji's digicams, but Minolta went from F9 on the Dimâge 7x to F11 on the Ax. I think this is not really a trend, but rather different from model to model. But I see Fuji getting further and further behind in the prosumer segment. Of course, in the Pro segment they've got lots of respect for their S3 Pro.

AZ

[spadnos]

Good for Minolta!

I personally like to get enough rope to hang myself with.

- Steve

[VJ]

Wouldn't this 'decrease' in aperture range have to do with the fact that the absolute aperture size is small to begin with ? (hence: technically more complex to make the opening very small)

Slightly on topic:
the influence of smaller imaging sensors on the DOF:

http://www.wrotniak.net/photo/dof/

Jörg

[az]

VJ, the lens (and sensor size) on the Dimage 7 series and Dimage A series is the same, save for the smaller minimum aperture, so it must me something other than pure physical reasons.

AZ

[VJ]

Yes, but in Minolta's case, it is an improvement... In TP's example (2.8-11 -> 2.8-7), the range gets worse...


Jörg

[The PIT]

The miniumum aperture size hardly ever appears on the specs. The range ideally should be getter larger not smaller. Is it that larger pixal cameras aren't sensitive enougth?
The only reason why I suggest this that under less than ideal conditions your forced to go say 2.8 as it's the only way you can the correct exposure without camera shake.

[Wulfman]

Originally posted by The PIT
The miniumum aperture size hardly ever appears on the specs. The range ideally should be getter larger not smaller. Is it that larger pixal cameras aren't sensitive enougth?

you might be there at something - the small sensors could easily lack the sensitivity to handle bigger apertures.

mfg
wulfman

[az]

I don't think that's the reason. The Dimage A1 has 5mp just like the D7, but a smaller minimum aperture. The A2 has 8mp and the same minimum aperture as the A1, and all have the same lens (except the aperture).

What I'm trying to say is, I don't think there's a technical reason. Maybe it's cheaper for Fuji not to allow very small apertures. Maybe their new lens design (The S7k does have a new lens, doesn't it?) doesn't allow for such small apertures. But really, the S7k was quite a miss on the prosumer market, IMHO.

AZ

[The PIT]

Most others though also stop at eight though the A2 is the exception rather than rule.

[spadnos]

Actually, they may be stopping at f8 for a reason.
I can't find the article I got this from - I'll post it when I do.

Basically, when you go through the range of apertures of a lens, the wider apertures (lower f numbers) have good resolution, but bad focus. The resolution of the lens will be the controlling factor for these apertures. Higher f-stops have better focus, but at some point, the diffraction limit of the lens takes over from the "resolution" of the lens as the controlling factor. Usually, the sweet spot is around f8 or so.
As the pixel sizes get smaller and smaller, the diffraction problem starts at a wider aperture (basically, if the light might move over to an adjacent pixel, you have a problem)

Hope this was coherent - I haven't had my coffee yet.

- Steve