Pre-AI Lenses: I have some legacy pre-AI lenses that were used on a Nikon F camera during the 50's and 60's. I had them converted by John White, who I highly recommend, to adapt to a...

MRHooker2u Loc: Kingston, WA

I have some legacy pre-AI lenses that were used on a Nikon F camera during the 50's and 60's. I had them converted by John White, who I highly recommend, to adapt to a Nikon D750. The lenses work quite well with the D750 and I am more than pleased with the results. My question is: When setting the scene the exposure values are off from the values suggested by PhotoPills. Case in point - The EV value for a bright overcast day is 13. For an aperture of F8.0 @ 100 iso the time value should be 1/125 sec. With those settings the exposure is way too dark. What appears natural is a setting of 1/20 of a sec. Is this a result of using pre-AI lenses on a DSLR? Thanks for your insight.

Screamin Scott Loc: Marshfield Wi, Baltimore Md, now Dallas Ga

Why not just use the in-camera meter and adjust as needed? setting settings by an app, to me anyway, is akin to using the old Sunny 16 rule, meaning it isn't as accurate as it can be.

MRHooker2u wrote:

I have some legacy pre-AI lenses that were used on... (show quote)

Bipod

MRHooker2u wrote:

I have some legacy pre-AI lenses that were used on... (show quote)

Very interesting question. I use a lot of pre-AI Nikon lenses, but haven't tried them on a
Nikon digital camera However, I'm familiar with lenses that have been converted to AI.

As you know, the D750 has the AI "finger" -- you can check that it is working by looking
at the aperture number in the viewfinder, then comparing the lens aperture ring. Almost
certainly it is working perfectly.

The problem isn't AI or mechanical focus, it's that the lens isn't a CPU lens that reports all
its data electronically. So according to what I've read, there is an extra step you need to
do in the camera's setup before you use one of these lenses. Basically, you need to tell it
about the lens. Right now, it is defaulting to something that isn't working for you

Here's how:
https://www.slrlounge.com/how-to-use-old-legacy-lenses-on-your-modern-nikon-dslr/

Please let us know if this works. It's very likely I'll be in your situation someday soon--
I don't plan on giving up these excellent prime focus Nikkor lenses.

pesfls Loc: Oregon, USA

I suspect bipods answer is your issue, at least it would be on my Df body. So does your 750 have a menu item called “non cpu lenses”? If so enter the data for the lens you want to use and select it. If that’s the issue all will be well and your meter will read as you wish. Hope this is helpful but admit I’ve not used a 750 so am not certain. Worth a look. Good luck.

BebuLamar

Is the lens is an F3.5 lens? If so I suspect that it's not correctly converted to AI.

wingclui44 Loc: CT USA

MRHooker2u wrote:

I have some legacy pre-AI lenses that were used on... (show quote)

I am using several Pre AI, AI converted; AI and AIS, lenses with my Df, I don't have any issue. Did you enter all the lens data to the camera before taking picture. You have to select the lens in the manual when using the lens, so the camera will set the exposure according to the data.

MRHooker2u Loc: Kingston, WA

I have already paired the lenses to the camera so when I use the 28mm f3.5 or the 50mm f2.0 etc... and tell the camera which lens is installed the camera responds accordingly.

Screamin Scott Loc: Marshfield Wi, Baltimore Md, now Dallas Ga

If you have an older handheld meter, see what settings that suggests...Those suggestions from that Photopills app may not necessarily correspond to what you think the scene is....

MRHooker2u Loc: Kingston, WA

My question revolves around the EV values and settings. According to the the EV table for a heavy overcast day using a lens set to f8 and ISO 100 the shutter speed should be 1/60 sec. At this setting the photograph appears almost black. The camera meter shows the shutter speed should be set to 1/4 to 1/2 sec. with the photograph appearing more normal. If I adjust the lens to f4 at ISO 100 the EV table shows the shutter speed should be 1/250. The camera meter shows the shutter speed should be set to 1/3 sec. (not much different than the f8 reading. Is the EV table and/or PhotoPills wrong or does the camera use a different algorithm to calculate light sources? Any further thoughts?

User ID

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I use many of my zillion ai converted and ai
lenses, nikkor , sigma, etc, on my 750. There
are no special tricks involved. I use them just
the same way I used them on 1970's era film
bodies. That said, be sure you're not trying to
use them the way you might use a D or G AF
Nikkor on a 21st century Nikon ! IOW stick to
1970's methods, modes, etc and all is cool :-)

Note I did not say ALL of my zillion .... check
that the full range of f/stops responds to the
control ring, by direct observation with DoF
preview engaged. If the stopdown arm on
the back of a lens hangs up on some piece
of the mirror box interior, some f/stops may
not be what the control ring numbers say
that they are ! This would be an instance of
mechanical collision. Total incompatibility.
No special tricks will cure it.

.

User ID

pesfls wrote:

I suspect bipods answer is your issue, at least it would be on my Df body. So does your 750 have a menu item called “non cpu lenses”? If so enter the data for the lens you want to use and select it. If that’s the issue all will be well and your meter will read as you wish. Hope this is helpful but admit I’ve not used a 750 so am not certain. Worth a look. Good luck.

Far as I can tell, the "non CPU lens data" thingy
in the menu does nothing more than correct the
exif and VF readings so that they read in f/stop
numbers instead of sequential integers. If you
ignore it, you f/stops are called "1,2,3, ... etc"
instead of the "official" f/stop numbers, BUT it
has no other purpose that I can determine.

The "1, 2, 3 ..." works just fine. Itell you how
many stops down you are from max wide open.
Could use red, orange, yellow ..... blue" instead
of numbers and would not matter. If you look
at the nubers on an ai control ring, they are all
color coded anyway, to match the DoF scale :-)

.

Pablo8 Loc: Nottingham UK.

User ID wrote:

Far as I can tell, the "non CPU lens data&quo... (show quote)

The "1,2,3," works for me , with my older Nikkor lenses. As long as you have 'Registered' / Entered the details of the particular Non-CPU lens in the Digital Camera body menu, you can read how many stops down from full aperture the lens is set.

Bipod

MRHooker2u wrote:

My question revolves around the EV values and sett... (show quote)

EV tables are not nearly accurate enough to draw any conclusion.
How heavy is the overcast? What time of day? What is latitude? What season?

As a previous poster suggested, the OP should get his hands on a light meter.

Architect1776 Loc: In my mind

MRHooker2u wrote:

I have some legacy pre-AI lenses that were used on... (show quote)

As suggested before, use the camera meter. An amazing invention from a few decades ago that reads the actual light coming through the lens. I us Pre-AI lenses on my 7D frequently with absolutely no problem by letting the camera determine the exposure.

jeweler53

According to the manual (P.235) "Non-CPU lenses can be used in modes A and M, with the aperture set using the lens aperture ring." This is the same on the Df.

Set the camera up so that it knows what lens is on the camera. It needs to be specified in the "Non-CPU" settings if it does not have a chip. Use the meter in the camera. It is WAY more accurate than a EV table.