Nikon D70 depth of field preview button doesn't work. What to do?

February 19, 2008 3:33 AM

I just bought a used Nikon D70, and so far it's great except for one small problem. The depth of field preview button doesn't seem to work.

When I look into the front of the lens I can see the aperture change size when I push the button, so I guess that part is working ok, but when I look through the viewfinder it's completely black. It sounds like the mirror is locked up when I push the button, which would explain why I can't see anything through the view finder, but this doesn't make any sense to me. I've tried in both A and M modes, with both 50mm and 18-55mm lenses and no luck.

At this point I suspect operator incompetence more than something wrong with the camera, but I need to find out as soon as possible so that I can return it if necessary. I have googled, and it seems that several other people have had this problem, but nobody has posted solutions. So I turn to you, hive mind. Am I doing something wrong, or is something wrong with my camera, and what can I do in either case?

posted by benign to technology (12 comments total)

This doesn't sound right. Can you see anything through the viewfinder, before you push the DoF button?
posted by zippy at 3:40 AM on February 19, 2008

I think it's working fine. If you have the aperture set to f22 or something like that (small), and you press the DOF button, it shuts the aperture to what you are shooting at. So yeah, it will make it very dark, particularly if you are inside in low light.

What it does is allow you to check what's in focus and what's out of focus, but at the price of reducing the amount of light coming in. It's only moderately useful to me, because it's hard to tell what's in focus because there isn't much light coming in.

From your description it sounds like it's working exactly right.
posted by sully75 at 4:04 AM on February 19, 2008

I've tried setting the aperture to everything from 1.8 to 22 and it's always pitch black, no matter what. I'm familiar with what the button should do since I used an old Minolta film SLR on which it worked correctly, and it's definitely not doing that.

I can see fine through the viewfinder before pushing the button, and can take photos normally, it's just this button that doesn't work. I'm aware that it's not particularly useful on a digital camera, but I'd still like everything to work correctly, or at least to find out if I'm doing something wrong.
posted by benign at 4:18 AM on February 19, 2008

can you see instead through the lcd on the back? Many SLR cameras use the widest aperature for looking through the viewfinder so you can actually see what you're doing. Go out into bright light and then see if it works. Try making sure you're at a wide F-stop (like f4 or 2.8 or whatever the highest is for the lens you're using).

Or maybe the mirror flips up an you have to look on the back LCD instead for that feature?

I'm just guessing here as I'm a Canon user.
posted by hylaride at 4:55 AM on February 19, 2008

Huh. that sounds busted then. I'd double check the manual. at 1.8 or whatever the lens is wide open it shouldn't be doing anything.

It might have a double function, but I don't know. I shoot canon.
posted by sully75 at 5:20 AM on February 19, 2008

Have you done a reset of all settings to factory defaults? I am not aware of any ability to remap that button in the D70 but I own an 80 so I can't say for sure.

I'd do that to make sure there's no weird remap.
posted by phearlez at 7:29 AM on February 19, 2008

Did you get a good deal on the camera? Although it does appear broken somehow, does this really matter to you, especially on a digital camera? You are going to get instant feedback after the shot to see whether you had sufficient depth of field.

When you say it sounds like the mirror is locked up, do you actually mean you hear the sound of the mirror flipping up? It is a distinctive sound. If that is the case, something odd is happening. The best person to ask may well be the person who sold you the camera. You are using a CPU lens correct?
posted by caddis at 8:04 AM on February 19, 2008

I agree with sully75 - I have the same "issue" with my D70 and it is due to the aperture, available light, etc since you are now seeing exactly what the sensor would be seeing.

If you try this outside on a very sunny day it should hopefully be a better preview - unless something is actually broken like others say.
posted by JibberJabber at 8:37 AM on February 19, 2008

Yes, I believe it is the sound of the mirror flipping up. It seems to flip up when I press the button and fall back down again when I release it. Also, yep, both lenses that I've tried it with are CPU lenses. I guess I'll give the seller a call tomorrow and ask him what's up. It WAS a pretty good deal, and no it doesn't REALLY matter. I'd mostly just feel better if it worked, and imagine I might like to use it if/when I try some macro stuff.

JibberJabber: If you point your camera directly at a light source, like a light bulb, or a monitor, and press the depth of field preview button, with your aperture as wide as possible, can you see anything through the view finder? I tried this with both lenses, and all was still pitch black. Also, do you hear this mirror flipping sound when you press/release the button?
posted by benign at 8:56 AM on February 19, 2008

Are you sure it's not a mirror lockup button instead of a dof preview button? Because that's exactly what a mirror lockup button does. It flips the mirror after you compose the shot (on a tripod) so that the mirror doesn't contribute any camera shake when it flips up.

I'm betting that it's somehow changed in custom settings. But again, I know nothing.

I really wish I was as knowledgeable about women as I am about cameras.
posted by sully75 at 10:02 AM on February 19, 2008

The D70 does not have a mirror lock-up feature (one more way to sell more "pro" cameras). You can put the mirror up to clean the sensor, but you can not actuate the shutter while it is up, and this is done through a menu option and then pressing the shutter release, not with a mirror lock-up button.
posted by caddis at 11:07 AM on February 19, 2008

You don't need to be outside on a sunny day. Simply set your mode to aperture priority and crank it down to the lowest setting on your lens, a 3.5 on that 18-55 if I remember correctly.

With the ap fully open you should see absolutely no chance when pressing the preview button.
posted by phearlez at 12:19 PM on February 19, 2008