letus extreme w/ nikon and canon lenses? at DVinfo.net

Bruce S. Yarock · November 17th, 2009, 02:02 AM

I bought my Letus extreme with the nikon adapter, and managed to put together a nice inexpensive collection of older nikon primes. I recently added the canon 7d to my arsenal, and got several canon lenses, some of which I'd love to use on the Letus also.

How practical would it be to switch adapters on a shoot? I've heard that you have to re adjust the back focus when you go from one adapter to another. Also, would the Letus backfocus ring make this process a lot easier and more practical?
Thanks
Bruce Yarock
Yarock Video and Photo

Bob Hart · November 18th, 2009, 10:35 AM

You can buy adaptors to mount Nikon lenses to Canon EOS-Mount. If you get one of good quality, this should take care of the backfocus issue and you could then make your EOS mount for the Letus the permanent mount.

There may still be some backfocus trimming required of the degree you might need between individual lenses of any type.

Bruce S. Yarock · November 20th, 2009, 07:47 AM

Bob,
I already have an adapter to mount the Nikons on my 7D. What I was talking about was the opposite...using the new Canon lenses I bought ( for the 7D) on the Letus rig. I understand that I'd have to buy the letus Canon mount, but my question was as to how practical it would be to switch back and forth between two different Letus mounts ( Nikon, which is on my Letus, and canon). Someone told me that you have to re adjust the back focus when you switch mounts on the Letus. if that's true, I was wondering whether that would be easier with the "elite" back focus ring ( which is not cheap-$600).
Bruce Yarock
Yarock Video and Photo

Gerdy Vandermeersch · November 20th, 2009, 09:02 AM

Hello Bruce.

I own the Letus Extreme and I've used the Nikon adapter, the Canon EF and Canon FD-adapter. So I own 3 adapters for the Extreme. You can't chance the backfocus on the Extreme... Then you have to buy the Elite or the Ultimate I thought. I somethimes do switch from the Canon FD to Canon EF-adapter for one project. And that goes fast for me. But I don't change the backfocus. I can't change the backfocus with the Extreme as I said.

The only zoom-lens I use is the Tamron EF 18-250mm and it's the only lens I have to adjust the sharpness when I use the zoom. But for me that's no problem because I don't use zoom-shots with my Extreme. When I use the zoom-lens, I take my frame and then hit the record-button. I actually use the only zoom-lens I have as a prime, if you know what I mean!

So what I want to say is that I use different adapters and lenses for one project and every image of the different lenses is as sharp as it should be!

Bob Hart · November 20th, 2009, 11:28 AM

Sorry Bruce.

I got confused. Maybe. - I am of the wrinkly generation so I am allowed to. You on the other hand have a few more years during which you are compelled to be sharp.

Now - to the mounts, - have to swap them you will??? Should not have to.

You will need to buy the Canon mount for your Letus.

I was thinking that you make the Canon EOS mount your permanent mount on the Letus, accurately backfocussed and all and then use the Canon-Nikon adaptor to fit your Nikons to the Canon mount rather than disturbing the Canon mount for sake of putting the Nikon mount back in.

I am imagining the Canon mount for the Letus Extreme will like the Nikon, have the same three little prop screws on axial centres in back of the ring for setting back-focus and optical axis alignment with the focal plane. Even if I had the Elite, I would still be checking and if necessary, trimming the axis alignment with these screws.

Provided you take the time and trouble with the camera hooked up to the biggest sharpest monitor and use a resolution chart, both mounts could be made accurate if you decided to use the separate mounts.

To be extra sure for repeatability, score a tiny matchmark on each mount and one on the Letus body so they always go in the same way.

When fixing the mount rings in the front of the Letus, make sure rearwards pressure is always applied. Lock the little prop screws with some nail polish or pinhead drop of loctite once the adjustments are found.

To avoid the possibility of the three allen screw tips "walking" the mount ring foward whilst being tightened, you might examine buying three similar screws and having the tips turned to an accurate conical point on a lathe. Don't overtighten these as they will tear up the bottom of the groove in the mount ring.

Bruce S. Yarock · November 21st, 2009, 01:22 AM

Bob,
Thanks for the info. Btw, I too am part of the "wrinlkly generation". Born feb. 12 1948.:)
Bruce Yarock

November 17th, 2009, 02:02 AM	#1
Bruce S. Yarock Trustee Join Date: May 2004 Location: Pembroke Pines, Fl. Posts: 1,842	letus extreme w/ nikon and canon lenses? I bought my Letus extreme with the nikon adapter, and managed to put together a nice inexpensive collection of older nikon primes. I recently added the canon 7d to my arsenal, and got several canon lenses, some of which I'd love to use on the Letus also. How practical would it be to switch adapters on a shoot? I've heard that you have to re adjust the back focus when you go from one adapter to another. Also, would the Letus backfocus ring make this process a lot easier and more practical? Thanks Bruce Yarock Yarock Video and Photo

November 18th, 2009, 10:35 AM	#2
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,476	You can buy adaptors to mount Nikon lenses to Canon EOS-Mount. If you get one of good quality, this should take care of the backfocus issue and you could then make your EOS mount for the Letus the permanent mount. There may still be some backfocus trimming required of the degree you might need between individual lenses of any type.

November 20th, 2009, 07:47 AM	#3
Bruce S. Yarock Trustee Join Date: May 2004 Location: Pembroke Pines, Fl. Posts: 1,842	Bob, I already have an adapter to mount the Nikons on my 7D. What I was talking about was the opposite...using the new Canon lenses I bought ( for the 7D) on the Letus rig. I understand that I'd have to buy the letus Canon mount, but my question was as to how practical it would be to switch back and forth between two different Letus mounts ( Nikon, which is on my Letus, and canon). Someone told me that you have to re adjust the back focus when you switch mounts on the Letus. if that's true, I was wondering whether that would be easier with the "elite" back focus ring ( which is not cheap-$600). Bruce Yarock Yarock Video and Photo

November 20th, 2009, 09:02 AM	#4
Gerdy Vandermeersch Regular Crew Join Date: Sep 2009 Location: Ieper, Belgium Posts: 75	Hello Bruce. I own the Letus Extreme and I've used the Nikon adapter, the Canon EF and Canon FD-adapter. So I own 3 adapters for the Extreme. You can't chance the backfocus on the Extreme... Then you have to buy the Elite or the Ultimate I thought. I somethimes do switch from the Canon FD to Canon EF-adapter for one project. And that goes fast for me. But I don't change the backfocus. I can't change the backfocus with the Extreme as I said. The only zoom-lens I use is the Tamron EF 18-250mm and it's the only lens I have to adjust the sharpness when I use the zoom. But for me that's no problem because I don't use zoom-shots with my Extreme. When I use the zoom-lens, I take my frame and then hit the record-button. I actually use the only zoom-lens I have as a prime, if you know what I mean! So what I want to say is that I use different adapters and lenses for one project and every image of the different lenses is as sharp as it should be!

November 20th, 2009, 11:28 AM	#5
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,476	Sorry Bruce. I got confused. Maybe. - I am of the wrinkly generation so I am allowed to. You on the other hand have a few more years during which you are compelled to be sharp. Now - to the mounts, - have to swap them you will??? Should not have to. You will need to buy the Canon mount for your Letus. I was thinking that you make the Canon EOS mount your permanent mount on the Letus, accurately backfocussed and all and then use the Canon-Nikon adaptor to fit your Nikons to the Canon mount rather than disturbing the Canon mount for sake of putting the Nikon mount back in. I am imagining the Canon mount for the Letus Extreme will like the Nikon, have the same three little prop screws on axial centres in back of the ring for setting back-focus and optical axis alignment with the focal plane. Even if I had the Elite, I would still be checking and if necessary, trimming the axis alignment with these screws. Provided you take the time and trouble with the camera hooked up to the biggest sharpest monitor and use a resolution chart, both mounts could be made accurate if you decided to use the separate mounts. To be extra sure for repeatability, score a tiny matchmark on each mount and one on the Letus body so they always go in the same way. When fixing the mount rings in the front of the Letus, make sure rearwards pressure is always applied. Lock the little prop screws with some nail polish or pinhead drop of loctite once the adjustments are found. To avoid the possibility of the three allen screw tips "walking" the mount ring foward whilst being tightened, you might examine buying three similar screws and having the tips turned to an accurate conical point on a lathe. Don't overtighten these as they will tear up the bottom of the groove in the mount ring.

November 21st, 2009, 01:22 AM	#6
Bruce S. Yarock Trustee Join Date: May 2004 Location: Pembroke Pines, Fl. Posts: 1,842	Bob, Thanks for the info. Btw, I too am part of the "wrinlkly generation". Born feb. 12 1948.:) Bruce Yarock