Non-CPU lens Data question

mguffin

Senior Member
I have a Nikon Series E 75-150mm f/3.5 lens, and am trying to understand the best way to identify it as a Non-CPU lens. There is no selection (in my D610) for either 75mm or 150mm. Should I be using something in the middle, or closer to one end or the other, or maybe it doesn't matter...?
 

BackdoorArts

Senior Member
You're going to be absolutely manual with this lens on both focus and exposure. Set shutter speed appropriately on the camera and adjust the aperture manually on the lens. The camera can't help you beyond capturing the exposure you give it. If you don't have an external meter then read up on the "Sunny 16" rule and start with that.
 

mguffin

Senior Member
You're going to be absolutely manual with this lens on both focus and exposure. Set shutter speed appropriately on the camera and adjust the aperture manually on the lens. The camera can't help you beyond capturing the exposure you give it. If you don't have an external meter then read up on the "Sunny 16" rule and start with that.

Ummm, thanks, but you didn't even come close to answering my question. I understand how to focus and expose with manual glass.

Furthermore, the lens does expose properly when using Aperture Priority, so there is no need for an external meter.

As for my question, when entering the info into the camera as a Non-CPU lens, since it's a zoom, should I select a value closer to one end or the other or in the middle...?
 

BackdoorArts

Senior Member
Funny, but every compatabilty chart I've seen says that the lens will not meter properly. If it works, great.

My understanding (which is now obviously suspect) is that the focal length data you enter has nothing to do with metering and is only used as a pass-along for EXIF metadata.
 

mguffin

Senior Member
From the D610 manual:

  1. Specifying both the focal length and maximum aperture of the lens:
    • Enables color matrix metering (note that it may be necessary to use center- weighted or spot metering to achieve accurate results with some lenses, including Reflex-NIKKOR lenses)
    • Improves the precision of center-weighted and spot metering and i-TTL balanced fill-flash for digital SLR
 

BackdoorArts

Senior Member
Well given that you have a range of focal lengths it would seem you're free to pick one, or would need to enter several and adjust that as you zoom in or out. Not convenient, but if you're looking for ultimate accuracy it's your only choice. You say it's metering fine without the additional accuracy, so I suspect that something around 105mm would do ya.
 

Jezzce

Senior Member
I have a Nikon Series E 75-150mm f/3.5 lens, and am trying to understand the best way to identify it as a Non-CPU lens. There is no selection (in my D610) for either 75mm or 150mm. Should I be using something in the middle, or closer to one end or the other, or maybe it doesn't matter...?

The selection is just a label, it doesn't matter what label you use, as long as you remember what you used.
 

mguffin

Senior Member
The selection is just a label, it doesn't matter what label you use, as long as you remember what you used.

In the manual it says that selecting the max aperture and focal length enables matrix metering, and improves spot and center weight metering...
 
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