D5100 & old lens?

[rdp6]

So, I am a SLR noob. We happen to have a Nikkor 70-210 f/4 lens from back when my wife took a photography class. It is AF but not AF-S so it can be mounted on our new D5100 (love it), but the camera insists that the lens' aperture ring be set to the smallest possible pupil. My limited understanding is that this limits the amount of light and that is generally a bad thing for the exercise of capturing light.

Can anyone help me understand why this is so?

Also, I am planning on getting the 35mm 1.8 DX lens, Nikon clear filter, SB-400 and if the 70-210 f/4 is basically useless for the D5100 then I will be considering either the 55-200 VR or the 55-300 VR. I can't seem to find any major discriminators for either. I am comfortable with staying with DX lenses for now and keeping costs down as I won't be making any money with the camera. Thoughts?

Also, Ken Rockwell's site has loads of info and I dig his "get past the specs" approach.

 

[iGas]

So, I am a SLR noob. We happen to have a Nikkor 70-210 f/4 lens from back when my wife took a photography class. It is AF but not AF-S so it can be mounted on our new D5100 (love it), but the camera insists that the lens' aperture ring be set to the smallest possible pupil. My limited understanding is that this limits the amount of light and that is generally a bad thing for the exercise of capturing light.

Can anyone help me understand why this is so?

Also, I am planning on getting the 35mm 1.8 DX lens, Nikon clear filter, SB-400 and if the 70-210 f/4 is basically useless for the D5100 then I will be considering either the 55-200 VR or the 55-300 VR. I can't seem to find any major discriminators for either. I am comfortable with staying with DX lenses for now and keeping costs down as I won't be making any money with the camera. Thoughts?

Also, Ken Rockwell's site has loads of info and I dig his "get past the specs" approach.

Nikon AF Nikkor 70-210mm f/4

According to Ken Rockwell the lens is very sharp except for the AF error due to Nikon first poor ass attempt at auto focusing. I would stick with the lens and use manual focus in aperture priority mode if it is a possibility. Unless you want a newer lens with working AF ability.

 

[xchangx]

So, I am a SLR noob. We happen to have a Nikkor 70-210 f/4 lens from back when my wife took a photography class. It is AF but not AF-S so it can be mounted on our new D5100 (love it), but the camera insists that the lens' aperture ring be set to the smallest possible pupil. My limited understanding is that this limits the amount of light and that is generally a bad thing for the exercise of capturing light.

Can anyone help me understand why this is so?

Also, I am planning on getting the 35mm 1.8 DX lens, Nikon clear filter, SB-400 and if the 70-210 f/4 is basically useless for the D5100 then I will be considering either the 55-200 VR or the 55-300 VR. I can't seem to find any major discriminators for either. I am comfortable with staying with DX lenses for now and keeping costs down as I won't be making any money with the camera. Thoughts?

Also, Ken Rockwell's site has loads of info and I dig his "get past the specs" approach.

It's normal for the lens to lock at f22 or whatever max aperture the lens is at. Once you mount it the camera will adjust the aperture.

 

[sswingle]

Yea, that annoyed me on my D3100 as well. If you are in live view you can't change aperture without leaving LV and going back, which means stopping recording if you are doing video. I was all excited thinking I could control aperture on the lens itself and then the camera won't let me.

But more to your question, its normal because the camera is controlling aperture, not the lens itself.

 

[twistedlogic]

Also, I am planning on getting the 35mm 1.8 DX lens, Nikon clear filter, SB-400 and if the 70-210 f/4 is basically useless for the D5100 then I will be considering either the 55-200 VR or the 55-300 VR.

The 70-210 is not useless, just crippled as it will not AF on the D5100. If you can afford, skip the 55-200/55-300 for the Nikon 70-300 VR or Sigma 70-300 OS. Much faster AF and the optics work on film and FX cameras. Nothing wrong with the 55-200/300 optics, they just use the much slower AF-S motor.

 

[twistedlogic]

But more to your question, its normal because the camera is controlling aperture, not the lens itself.

Well both. The aperture is set in camera, and while mounted and looking thru the VF the aperture is locked wide open. Once the shutter trigger is released the camera body moves a little lever located on the mount of the lens, which mechanically moves the aperture blade located inside the lens, thus stopping down the lens (unless shot wide open).

 

[Munky]

So you're saying it's impossible to directly control the aperture on the lens with a modern DSLR? What if you use Manual exposure mode, and set the aperture on the lens anyways?

 

[rdp6]

For sure the aperture dial on the lens must be set to the smallest opening, i.e. f/32 else the camera tells you to make it so. Despite this I took photos which have EXIF data showing apertures all over the place. I managed to catch a bee on a flower at max zoom (lens + real distance) more or less in focus. Had to focus with my feet near the limit. Depth of field seems pretty shallow around f/8!

I wonder what is the purpose of the lens' pupil ring? I have a short list of ideas but they all seem absurd. Maybe only used with fully manual bodies (FM10)? Do AF capable bodies also require stopping the pupil all the way down?

As for faster (f/2.8 teles) and FX lenses, that is in my mid-career budget. Still E1 engineer for now. Anyways, it will be nice to pass a complete DX set to my daughter in 6 years.

ps: the D5100 does not change the pupil ring. Is it possible for the pupil to be opened by the camera?