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Archive 2009 · D70s - as I stop down, exposure...

  
 
DennisC
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p.1 #1 · D70s - as I stop down, exposure...


...increases. Is my camera ready for a visit to the shop?

However, a thought - my SS at f2.8 was 1/200 - not that fast. As I stop down, the SS increases are not exactly linear. That is, for example, I had f11 at 1/15, then at f22, I was at 1/3, which is slower than what would be an exactly linear SS of 1/3.75. Am I making any sense whatsoever?

D70s, 17-55 f2.8, matrix, aperture priority, at f-stops 2.8, 5.6, 11, 22, respectively.

http://farm4.static.flickr.com/3650/3684494450_4e75cb4ed0_o.jpg

http://farm3.static.flickr.com/2562/3683681561_b727b1ff6a_o.jpg

http://farm3.static.flickr.com/2590/3683681705_25f6483219_o.jpg

http://farm3.static.flickr.com/2645/3684494810_89fc4979a5_o.jpg



Jul 03, 2009 at 08:04 AM
Steve Perry
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p.1 #2 · D70s - as I stop down, exposure...


Those pictures do seem to get brighter as you go down. If I were to guess, I'd wonder if your lens was stopping down properly at the time of exposure. Can you try it with a different lens?

As for everything not being 100% linear as you stop down, keep in mind that many times there are slight variances in the outdoor light that account for slight variations in exposure. In order to test it, you'd have to be in a controlled lighting situation. Plus, I think sometimes that the metering is kind of teetering between 1/3s, so you sometimes get a bit of variance there as well.

Overall - again, if I'm understanding what you're asking - I think everything seems normal.

Steve



Jul 03, 2009 at 08:21 AM
DennisC
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p.1 #3 · D70s - as I stop down, exposure...


Thank you, Steve.

I just tried again in very bright light - same thing happens. I tried with my D2Hs in dim and bright light, again, same experience.

I did notice the same thing last week while on vacation with my 70-200VR; so it appears to NOT be body or lens. I suppose it is the variation you speak of; however, such a big, to me, difference in the overall brightness is not what I would have expected.

More study warranted here.

Thanks for replying!



Jul 03, 2009 at 08:25 AM
Steve Perry
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p.1 #4 · D70s - as I stop down, exposure...


Hmm...

The slight variation you sometimes see in exposure should only be 1/3 of a stop one way or another - you seem to be a lot further off than that.

Are you saying the D2h is doing the same thing as the D70? What do your histograms look like? For equal exposures, (i.e. f8 @ 1/125 or f5.6 @250) the histograms should be identical. If they are going up towards the right (which looks like what's happening based on your photos), then something's wrong somewhere.

Steve



Jul 03, 2009 at 08:44 AM
DennisC
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p.1 #5 · D70s - as I stop down, exposure...


Yes, I experienced the same phenomena with my D2Hs; and, yes, the histograms are creeping to the right.

Wierd.



Jul 03, 2009 at 10:19 AM
Steve Perry
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p.1 #6 · D70s - as I stop down, exposure...


Both cameras do it with any lens? Wow, that's just not making any sense at all. Hopefully someone else has an idea or two.


Jul 03, 2009 at 10:28 AM
runamuck
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p.1 #7 · D70s - as I stop down, exposure...


My D700 (indoors, artificial light, drapes drawn) goes
f2.8 and 1/2 second
f4 gets 1/15 second
f5.6 is 1/8 second
f8 = 1/4 second
f11 = 1/2 second
f22 = 2 seconds

It's not truly linear, but the histograms are pretty much identical, within about 1/3 stop. On the computer they look almost exactly the same. At least to my eyes.



Jul 03, 2009 at 02:11 PM
Avi B
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p.1 #8 · D70s - as I stop down, exposure...


f2.8 gets 1/2 second and f4 gets 1/15?? something doesn't sound right...



Jul 03, 2009 at 02:31 PM
runamuck
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p.1 #9 · D70s - as I stop down, exposure...


Avi B wrote:
f2.8 gets 1/2 second and f4 gets 1/15?? something doesn't sound right...

I don't type so good sometimes,
and my eyes aren't all that good,
dyslexia creeps in and out,
and I'm worthless as a poet.

Anyway, I double checked, and it's 1/20. Still not quite linear, but that's what the meter says.



Jul 03, 2009 at 03:18 PM





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