Increasing FFD temporarily - Nikon or Canon mounts

[Kristian Schumacher]

Hi,

 

I have a small problem which is a bit unusual, I think. I use a 5d with an adapter and Nikon lenses. The lenses both focus a little bit past infinity, but that does not bother me. But I mainly focus on underwater filming, and I would like my two wide angles to focus a bit closer (one is Nikon 20m, one is Zenitar 16mm) They now have a focus limit of about .4-.5 m but I would like to make them focus down to 15-20 cm.

I guess theoretically I just need to have some chim in the mount to have a slightly greater ffd - but how can this be done in practice? I can put something either side of the adapter, or maybe buy some more adapters and hope to cet one that is a bit too thick?

 

Thanks for any advice,

 

Kristian

[Bernie O'Doherty]

Hi Kristian, you could try finding the smallest, thinnest, rubber band you can. Stretch it over the rear of the adaptor, past the threads. Screw it tightly on the camera. This might bring it out a little, so that you could have a closer focus.

Cheers, Bernie

[Kristian Schumacher]

Hi Kristian, you could try finding the smallest, thinnest, rubber band you can. Stretch it over the rear of the adaptor, past the threads. Screw it tightly on the camera. This might bring it out a little, so that you could have a closer focus.

Cheers, Bernie

 

Thanks for that Bernie,

 

It is not a screw mount though. The lens is nikon, the camera is Canon and the adapter between.

 

Kristian

[Bernie O'Doherty]

Well, you could try taking the adaptor apart ( I think that's the problem, because it's not to specifications). Normally there are 3 or 4 screws around the rear perimeter. Don't take the front apart because that will mess up the lens mounting correctly.

If you can take the rear apart, do so and insert a plastic shim, try around .5 mm to start. You can always go down to .3 or .2mm if need be. Any household plastic would be fine.

Tighten up again with the screws and hope for the best !

Cheers, Bernie.

[Kristian Schumacher]

Well, you could try taking the adaptor apart ( I think that's the problem, because it's not to specifications). Normally there are 3 or 4 screws around the rear perimeter. Don't take the front apart because that will mess up the lens mounting correctly.

If you can take the rear apart, do so and insert a plastic shim, try around .5 mm to start. You can always go down to .3 or .2mm if need be. Any household plastic would be fine.

Tighten up again with the screws and hope for the best !

Cheers, Bernie.

 

Thanks again Bernie,

 

I will give that a go. Just from a little testing it seems I want 2-3 mm though to get the close focus I want. But your way seems really good. I may need some longer screws to put is back together with a 2-3mm shim.

 

Kristian