depth of field button

[reijo]

I have a Nikon D300. It has a depth of field button but I have no idea how to use it.
All I can notice is that when I decrease the aperture from, say F5.6 to F22, is the scene through the view finder gets darker.
Am I missing something? Is my vision going?
Can anyone tell help me here.
Reijo

[Marko]

It's not the easiest button to use, but when you look through your viewfinder, you are seeing the scene through the LARGEST aperture on the lens regardless of what F stop your lens is set to. When you click the DOF preview button THEN you see the scene through your chosen aperture.

Since an aperture like F22 is small - the scene (as seen through that small hole) is darker. If you look carefully, you CAN see that the sharpness from foreground to background is SHARPER with an Fstop like F-22.
Try this during the day in bright sunlight and this will be clear. It's hard to do this in the house because it's dark.
Hope that helps
Marko

[Mad Aussie]

It's not the easiest button to use, but when you look through your viewfinder, you are seeing the scene through the LARGEST aperture on the lens regardless of what F stop your lens is set to. When you click the DOF preview button THEN you see the scene through your chosen aperture.

Since an aperture like F22 is small - the scene (as seen through that small hole) is darker. If you look carefully, you CAN see that the sharpness from foreground to background is SHARPER with an Fstop like F-22.
Try this during the day in bright sunlight and this will be clear. It's hard to do this in the house because it's dark.
Hope that helps
Marko

It helps me

I played briefly with this button on my Canon 400D when I got it and never understood. Recently upgraded to a Canon 40D and looked again at this and was no more the wiser at all. All I ever saw was a scene going darker. Now I know why!

[Mad Aussie]

Hmm can't say the button is very effective. Stepped outside, bright but overcast day. Used a 1:2.8 lens. When you choose a higher aperture the view darkens too much to see any difference anyhow. I'm sticking with trying out several aperture/shutter combos and choosing what I like best from the results. Gotta love digital.

[Michael Van der Tol]

Don' loose faith. The depth of field preview really isn't that useful at small apertures - too dark to see anything. Where you should be using it is on a really fast lens (f/1.4 to f/2.8 max aperture). Especially if your doing any macro photography. At these apertures you can usually get enough light into the lens to make a determination of the DOF. Sure you can go a head "pop" off a few shots to see how you did, but I still prefer the DOF preview for my macro shots.

[Mad Aussie]

Thanks for that extra input Michael ... helpful indeed

[dmagick]

Hmm can't say the button is very effective. Stepped outside, bright but overcast day. Used a 1:2.8 lens. When you choose a higher aperture the view darkens too much to see any difference anyhow. I'm sticking with trying out several aperture/shutter combos and choosing what I like best from the results. Gotta love digital.

Compare a low aperture (lowest your lens allows you to), then a mid-range (f-11) and then high (f22+). You will notice a difference between the 3, you won't notice much of a difference between say 4.5 and 5.6 (at least to start off with). I can't say I've used this feature much myself but if I ever get a macro lens it'll come in handy.

[mindforge]

With digital cameras today. Instead of getting a DOF preview, just take a shot and see what you got and delete it... I'll take a shot and zoom in to take a look. Better to take a minute or two to look at an actual shot and then start shooting. I really can't see any purpose behind a DOF preview.