Poor results with Nikon 28/2.8 AIs!

I bought a top condition Nikon 28/2.8 AIs lens.

I tested it on a Sony a6000, and the results are so-so in the corners, going from bad to okay from 2.8 to 5.6.

As this lens has a floating elements formula, I suspect it is due to my K&F Concepts adapter, infinite being on '3 meters'!

Would you know of an adapter Nikon Ai - Sony E (and I need also Nikon AI - M43) that is accurate in terms of focusing distance?

Thanks.

Belgarchi said:

I bought a top condition Nikon 28/2.8 AIs lens.

I tested it on a Sony a6000, and the results are so-so in the corners, going from bad to okay from 2.8 to 5.6.

As this lens has a floating elements formula, I suspect it is due to my K&F Concepts adapter, infinite being on '3 meters'!

Would you know of an adapter Nikon Ai - Sony E (and I need also Nikon AI - M43) that is accurate in terms of focusing distance?

Thanks.

Click to expand...

I wouldn't blame the adapter. I also have the K&F Concept G-NEX adapter. It also hits infinity about 3m on my NEX-5T with my AI-S 28/2.8. It should be pointed out that infinity and 2m are next to each other, so 3m isn't that far from the infinity stop... maybe 5 degrees.

Anyway, mine is really sharp in the corners, even at F2.8.

Belgarchi said:

I bought a top condition Nikon 28/2.8 AIs lens.

I tested it on a Sony a6000, and the results are so-so in the corners, going from bad to okay from 2.8 to 5.6.

As this lens has a floating elements formula, I suspect it is due to my K&F Concepts adapter, infinite being on '3 meters'!

Click to expand...

You could try shimming the adapter for accurate infinity focus:

https://www.dpreview.com/forums/thread/4141980#forum-post-59401594

Heritage Cameras said:

Belgarchi said:

I bought a top condition Nikon 28/2.8 AIs lens.

I tested it on a Sony a6000, and the results are so-so in the corners, going from bad to okay from 2.8 to 5.6.

Click to expand...

Click to expand...

One of my favorite lenses on my NEX-7 was my Canon FD SSC 24/2.8 https://www.flickr.com/photos/lightshow-photography/tags/canonfdssc2428/

Heritage Cameras said:

Heritage Cameras said:

As this lens has a floating elements formula, I suspect it is due to my K&F Concepts adapter, infinite being on '3 meters'!

Click to expand...

You could try shimming the adapter for accurate infinity focus:

https://www.dpreview.com/forums/thread/4141980#forum-post-59401594

Click to expand...

Hmmm will have to test my 28mm 2.8Nikkor AIS, on my nex 5r. My setup will be slightly different as I will be adapting using a focus reducer.

Belgarchi said:

I bought a top condition Nikon 28/2.8 AIs lens.

I tested it on a Sony a6000, and the results are so-so in the corners, going from bad to okay from 2.8 to 5.6.

As this lens has a floating elements formula, I suspect it is due to my K&F Concepts adapter, infinite being on '3 meters'!

Would you know of an adapter Nikon Ai - Sony E (and I need also Nikon AI - M43) that is accurate in terms of focusing distance?

Thanks.

Click to expand...

you could measure the thickness of your adapted and see how close is to 28.5mm. If it is undersized than shimming could be an option.

For any other adapter thickness (flange distance) calculations here is a link to the various camera mounts: https://en.wikipedia.org/wiki/Flange_focal_distance

Just tested my nikkor 28mm 2.8 AIS. seems fine in the corners. Tested in my Sony nex5r with original speedbooster.


Nikkor 28mm 2.8 AIS at f2.8 focus 3m

The old kit



Weather permitting will go test some outdoor infinite shots.

First, the Nikon AiS 2.8/28 starts with serial numbers of 635001 and up, so sorry "bigley Ling" yours is the older Ai-version, that is not discussed here ...

Second, I use the Nikon AiS 2.8/28 adapted on my Sony A7 M2 and the results are very good, even in the corners, at all distances including infinity.

Maybe your AiS 2.8/28 has a slight midframe drop in resolution .... so the APS-C frame is affected...

Production of the AiS 2.8/28 started in 1981, that's 36 years ago. Over such a long span of time some sample variation might occur...

Most wide-angle lenses are best stopped down to F8-11in the corners, even the Sony FE 2/28 is no exception here...

X_Holger said:

First, the Nikon AiS 2.8/28 starts with serial numbers of 635001 and up, so sorry "bigley Ling" yours is the older Ai-version, that is not discussed here ...

Click to expand...

Thanks X_Holger for clarifying this. Maybe the I got lucky with this older AI version

Belgarchi said:

I bought a top condition Nikon 28/2.8 AIs lens.

I tested it on a Sony a6000, and the results are so-so in the corners, going from bad to okay from 2.8 to 5.6.

As this lens has a floating elements formula, I suspect it is due to my K&F Concepts adapter, infinite being on '3 meters'!

Would you know of an adapter Nikon Ai - Sony E (and I need also Nikon AI - M43) that is accurate in terms of focusing distance?

Thanks.

Click to expand...

I use a Fotga adapter on an A7 and it seems like the distance markings are close enough to be accurate. But then again, I use an old 2.8/24mm Nikkor Ai lens with that, so plenty of DOF. I also have a K&F concept adapter for an M Mount lens and those markings are clearly off, so I don't use that anymore - got a generic close focus adapter instead and that is more accurate and I can use HFD. I got a Beschoi adapter for a Minolta lens and that those markings aren't actuate either, so I ordered another Fotga to try. Anyways, from what I gather, machine tolerances aren't of the highest standard on these cheap adapters and it's a crapshoot at times with combinations. For example, if you get another K&F adapter, it might actually be more accurate I guess we get what we pay for...