BIGGER APERTURE = more brightness in screen?

Started Jul 14, 2012 | Discussions thread
olakiril2 Contributing Member • Posts: 639
Re: The viewfinder always uses the largest aperture

apaflo wrote:

olakiril2 wrote:

primeshooter wrote:

elliotn wrote:

PRW_Photo wrote:

So an f2.8 lens will be brighter than an f3.5 lens, and an f1.4 lens will be brighter than either of them.

The f1.4 lens will not give a brighter viewfinder image than the f2.8 lens on a modern DSLR.

+1 well said. 2.8 is the max.

Well I just said that in my D800 the viewfinder is brighter with f/1.4.

That might be in your case, and I'm not going to comment about that aspect.

But the fact is that on every DSLR ever made with a plastic screen as opposed to a ground glass screen the viewfinder aperture is limited by the micro prisms in the viewing screen, most commonly to between f/2 and f/2.5. I haven't seen where anyone has measured it on the D800, but I would be simply astounded if it is other than very close to from f/2.2 to f/2.5 (which is what various Nikon models have been measured at).

Now, you may "see" changes in both brightness and DOF. But if you compare what you think you see in the viewfinder to what the sensor actually gets, it won't be even close. Put an f/1.4 lens on the camera and compare the change you see between f/5.6 to f/2.8 and then from f/2.8 to f/1.4. And look at the DOF you see at f/5.6 and at f/1.4, take a shot at each aperture, and compare the DOF in the image to what you saw in the viewfinder. At f/5.6 the viewfinder shows you something very close to what the image will be, but not at f/1.4.

It depends on the lens that is used since it is sensitive to the angle of the light rays.

I saw a difference with the 85 1.4. With the 50 1.4, visible difference starts after 2. I guess it will be even worse for 24/28/35 1.4 lenses.

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