p.1 #1 · Stopping down destroys exposure [Reason Identified]
I'm trying to wrap my head around this one.
Here's the setup (same result on 2 cameras so I've ruled body out, D70 and D300 used).
D300 with Tokina 12-24mm at 12mm. Using center weighted metering, single point center auto focus and auto exposure. ISO 200. Aperture priority. It was aimed at the clouds and should have metered for the sky on all pictures, but once it goes off wide open; everything gets completely blown out.
Set 1:
Wide Open (f/4) at 1/1600th of a second.
F/5.6 at 1/800th.
F/8 at 1/400th.
F/11 at 1/200th.
I just don't get it. I've done more tests but the results are the same so I'll only post if someone asks. The lens absolutely sucks in shutter and program modes because it chooses apertures smaller than f/4, so the pictures are destroyed from blowing out.
Edited by Taylor Barrett on Jul 05, 2008 at 08:45 PM GMT
p.1 #3 · Stopping down destroys exposure [Reason Identified]
I think your metering technique is faulty. I would be using spot if I pointed it at the clouds. Also, clouds vary in density and intensity so I would never meter on a cloud unless I was just doing cloud pics. You seem to be in incident meter territory anyway.
That is what I use for my pics.
p.1 #4 · Stopping down destroys exposure [Reason Identified]
Believe me, I tried every combination and two cameras and this was the best settings combination. Also, this metering technique works perfectly for my 6 other lenses, so I highly doubt that's the (sole) culprit.
p.1 #6 · Stopping down destroys exposure [Reason Identified]
Make sure your lens is actually stopping down. Your exposures should be exactly the same, so there must be a mechanical problem with the aperture. Set your lens to f/22, press the DOF preview button, and look into the front of your lens with a flashlight. I bet the aperture is not actually stopping down.
p.1 #7 · Stopping down destroys exposure [Reason Identified]
rc12k wrote:
Is your lens actually stopping down? I had a Sigma a few years back that would stick sometimes.
That's a really good question - that would make complete sense. The aperture appears in the Exif data but it would explain everything... how could I test this?
p.1 #8 · Stopping down destroys exposure [Reason Identified]
This appears to be confirmed from Ben's test. I did the 50mm first and noted the difference between f/1.8 and f/22 when pressing the DOF preview button (it was a huge, obvious difference, obviously), then did the same with the 12-24mm at f/4 and f/22, and there was no change between apertures.
Now I'm sad. Time to speak with the seller.
Good detective work, fellows. I never would have suspected that. This is why I turn to Fred Miranda in a pinch
p.1 #9 · Stopping down destroys exposure [Reason Identified]
Was ISO staying the same? Or, it was on Auto and changing from shot to shot. You can check the EXIF. Another way to check the lens is to go to Manual , set the fixed ISO, and vary the aperture and the shutter speed manually.
p.1 #10 · Stopping down destroys exposure [Reason Identified]
gfiksel wrote:
Was ISO staying the same? Or, it was on Auto and changing from shot to shot. You can check the EXIF. Another way to check the lens is to go to Manual , set the fixed ISO, and vary the aperture and the shutter speed manually.
Like I said in the first post, the ISO was 200 for all shots. I am completely certain that the two previous to my last reply are correct because as they said, stopping down does not physically close the aperture up.
p.1 #11 · Stopping down destroys exposure [Reason Identified]
I have had exactly the same problem with the D200... but after say 100 pics, I could only shoot fully open with all my lenses. The problem was in the camera, the aperture lever mechanism was not functioning properly. I am not saying this is the case here, but it has to do with the aperture. Could be the lens not closing down, or it could be the camera not closing down anymore (like in my case). The D200 needed to go to service BTW.
p.1 #12 · Stopping down destroys exposure [Reason Identified]
gugs wrote:
I have had exactly the same problem with the D200... but after say 100 pics, I could only shoot fully open with all my lenses. The problem was in the camera, the aperture lever mechanism was not functioning properly. I am not saying this is the case here, but it has to do with the aperture. Could be the lens not closing down, or it could be the camera not closing down anymore (like in my case). The D200 needed to go to service BTW.
Guy
This is definitely the aperture, I did more tests in manual where I kept the shutter and ISO the same but changed the aperture and the pictures were the same no matter what the aperture was set to.
The body is a brand new D300 so hopefully that's not the issue, but I highly doubt it is because the previous owner couldn't find a single keeper with an aperture that wasn't f/4 now that I've asked him about it. My other lenses work fine.
p.1 #13 · Stopping down destroys exposure [Reason Identified]
I had the same issue with a Nikon 18-70mm. It took me a long time to figure out because I tend to shoot in very low light and in low light, the lens would have been at 2.8 anyway, but it would overexpose in bright light. Look on the body side of the lens. There's a small lever that controls the aperture, but it's spring loaded and you should feel some tension. On my lens, the spring had apparently popped out or got lost inside the lens. Had it fixed and it worked fine.
This might not be a costly repair, so if you got a good deal on the lens, you might want to keep it.
p.1 #15 · Stopping down destroys exposure [Reason Identified]
Those spots are the lens hood. I picked up the hood from a local store right after I bought that lens used. Apparently it was for a different lens. I am the one that sold Taylor the lens.
Taylor,
I'm replying to your email. We will get this worked out one way or another.
