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The PIT
8th March 2004, 10:33
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
8th March 2004, 10:48
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
8th March 2004, 12:07
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. :D

SpiralDragon
8th March 2004, 12:18
heh..... a few HMIs ought to do the trick... :D

spadnos
8th March 2004, 14:13
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
8th March 2004, 15:35
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
8th March 2004, 18:42
Good for Minolta!

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

- Steve

VJ
9th March 2004, 05:01
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
9th March 2004, 05:46
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
9th March 2004, 07:29
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
9th March 2004, 10:13
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
9th March 2004, 10:17
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
9th March 2004, 23:48
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
10th March 2004, 00:11
Most others though also stop at eight though the A2 is the exception rather than rule.

spadnos
10th March 2004, 08:30
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

az
10th March 2004, 13:33
This still isn't a reason though, IMHO. Reviewers usually shoot resolution tests with small apertures, and customers would clearly welcome the option of having an additional aperture, even with not-perfect quality (or they wouldn't shoot digital, and certainly not all-in-ones - though the better of those are more than good enough for almost all people).

The Dimage 7/A lens performs best at F5.6 IIRC, BTW.

AZ

Greebe
10th March 2004, 17:29
I think Steve has hit it on the nailhead. The diffraction effect for such a small aperature would indeed cause a meriad of headaches for the lens designer. AZ this is no small feat to deal with.

Funny how I keep finding my old Nikon 35mm setup fits the bill dispite it's size/weight/film drawbacks.

I've got an f2.8-32 range on my 100-300mm telephoto, miles ahead of anything pricewise a digital can touch.

VJ
11th March 2004, 05:35
Steve indeed has a good point.

Another issue could be the light fall-off: imaging sensors requires the light to hit the sensor almost perpendicular. If you have very small f-numbers, this could become an issue for the pixels near the edge of the sensor.
(it could be solved by correcting the pixels in postprocessing, but this might introduce additional noise if the correction becomes too much)

az
11th March 2004, 05:52
These are all valid reasons but still, why have Fuji taken away the smallest aperture (for the same sensor size, and a lens that is at least similar to the old one), and why have Minolta managed to add a smaller aperture for the same lens and same sensor size?

AZ

VJ
11th March 2004, 06:45
Minolta tries to improve their equipment, whereas Fuji thinks nobody cares ? :)


Jörg

The PIT
11th March 2004, 10:28
Got to admit I wouldn't recommend the s7000 despite being fairly easy too use. Pictures tend to be too noisy even at iso of 200 so god knows what 800 is like.