Weird Apertures with the 20D - DPChallenge Forums

09/26/2004 07:29:03 AM · #1

Hey guys. My 20D is working great, but I'm come across something strange. These are the aperture increments I've been getting with my 20D and Sigma 105mm F2.8:

2.8 3.2 3.5 4.0 4.5 5.0 5.6 6.3 7.1 8.0

This is the 10D and Sigma 105mm:

2.8 3.5 4.0 4.5 5.6 6.7 8.0

Looks like it's in 1/3 increments or something? Any thoughts?

BooZon

09/26/2004 07:35:14 AM · #2

I get the same on the 300D.

Nikon AF-S Zoom-Nikkor 28-70mm f/2.8D IF-ED

09/26/2004 07:36:30 AM · #3

Same thing with shutter speeds. 20D:

1/4, 1/5, 1/6, 1/8, 1/10, 1/13, 1/5, 1/20, 1/25, 1/30, 1/40, 1/50, 1/60, 1/80, 1/100, 1/125, 1/160, 1/200, 1/250, 1/320, 1/400, 1/500, 1/640, 1/800

10D:

1/4, 1/6, 1/8, 1/10, 1/15, 1/20, 1/30, 1/45, 1/60, 1/90, 1/125, 1/180, 1/250, 1/350, 1/500, 1/750, 1/1000.

Instead of doubling at every 2 faster shutter speeds, it doubles every 3 shutter speeds.

Hmmmmmmm.

Not as intuitive, but might give more control over exposures.

Or maybe ... I should just get my first morning coffee.

Or even better ... shouldn't I be out there taking pics?

Message edited by author 2004-09-26 07:37:54.

hopper

Canon EOS-80D

Canon EF 35mm f/2 IS USM

09/26/2004 07:38:37 AM · #4

copied from dpreview:

Available apertures will differ depending on the lens used, the list below represent 1/3 stop increments, 1/2 stop increments can be selected via custom function 6.

F1.0, F1.1, F1.2, F1.4, F1.6, F1.8, F2.0, F2.2, F2.5, F2.8, F3.2, F3.5, F4.0, F4.5, F5.0, F5.6, F6.3, F7.1, F8.0, F9.0, F10, F11, F13, F14, F16, F18, F20, F22, F25, F29, F32, F36, F40, F45, F51, F57, F64, F72, F81, F91 (exact range depends on lens used)

Morgan

Nikon D800

09/26/2004 07:39:08 AM · #5

My Nikons do the same thing Jacques. I believe that your assumption is correct. These are just smaller incremental steps for more precision in the exposure and for DoF.

In the electronic age, why should we be limited to older mechanical restrictions? The original f-stops and shutter speeds were formulated for the smallest incremental steps technologically possible in a mechanical design, while still being functional and practical for their day. I believe that they were combined for the best one stop incremental exposure too. So, if you change the aperture, then you should also change the shutter in order to maintain the smaller step increments.

By the way, a new camera body? Congratulations! But, you know it is a decease, right....an addiction, right?

Message edited by author 2004-09-26 07:42:19.

09/26/2004 07:48:38 AM · #6

Got it ... it's custom function 06. You can choose 1/3 or 1/2 increments. Not sure which one I will prefer.