Manual Lens Urth Nikon G to mirrorless adapter.

mike3996

Legend
Location
Finland
Urth EU sells a Nikon F to L-mount adapter for 30 €, and a Nikon G to L-mount adapter for 7 € more.

I first ordered the F-L adapter but fortunately I thought about it a bit and I canceled and went for the G-L adapter instead.

This G-L adapter has an aperture ring as one'd expect.

With my pre-AI Nikkors, the ring is wonderful. It works as a preset aperture ring, which is a most wonderful thing to have, when using a mirrorless camera. What it means is that you can have your lens set up for your taking aperture, and meter for it also in camera. Then you can twist the Urth adapter ring to open up the lens, no need to count clicks or anything. You can then focus. Then a simple twist closes the lens to the aperture your actual lens is set. In short, a good, error-proof way to toggle your old Nikkor lens between wide open and your preset "taking" aperture.

With my Ai Nikkor, it's the same story, same behavior. Nice!


With my AF Nikkor, same.


At the time of writing this post, I don't have any G Nikkors so I can't test that for you.


My adapter was Nikkor G to L mount but I think every mount is the same.

In summary, whatever your mirrorless camera is and you're looking to adapt old Nikkors on it, you do well to spend the extra to get a Nikkor G adapter by Urth. This was not a paid message.
 
Focussing wide-open and then stopping down to the taking aperture can cause a degradation in sharpness, as I quickly discovered when using legacy lenses on my Panasonic G1 (yep, 12 years ago :); I sold my last DSLR in 2010). Almost all legacy lenses suffer from focus shift, i.e. the optimal focus point varies with aperture. These days I focus at the taking aperture when it's between wide-open and f/8; for taking apertures smaller than f/8, like f/11 or f/16, I focus at f/8 and stop down further. Very easy to check with a mirrorless camera: focus wide-open, note the setting on the focus scale, focus again at f/8 and check the focus scale again. For most lenses you'll notice a difference.

Some lenses don't exhibit objectionable focus shift. Examples in my line-up that come to mind are the Zeiss Loxia 2.4/85, Voigtländer Apo-Lanthar 2/35 and the Minolta MD Macro 4/100.
 
Yes, focus shift is good to keep in mind.

For a rangefinder user that's something one can't get over anyhow. I asked about focus shift on SLR lenses some time ago, and @BrianS was not overly concerned about it.


After all, SLR lenses like my Nikkors have had automatic aperture stopdown for 5 decades. They always focused wide open and closed down for taking, so focus shift had to be well controlled when designing the lenses.

M4/3 cameras demand a tremendous amount of the lenses mounted in front of them. The bigger the sensor, more forgiving they are.
 
After all, SLR lenses like my Nikkors have had automatic aperture stopdown for 5 decades. They always focused wide open and closed down for taking, so focus shift had to be well controlled when designing the lenses.
Optical viewfinders with focus-aids like split-prims and micro-prisms behave like the aperture is at f/4 or so for focussing, depending on the design of the focus-aids; some special screens for the Nikon F3 were more effective for large-aperture lenses. With an EVF you're really focussing at the aperture set on the lens and this can make very noticeable differences. For instance, the Minolta MD 4/17 has a large amount of focus shift and the image at f/8 is just not sharp when the lens was focussed at f/4.
 
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