35mm Adapter focus issue?

i_am_remote

i_am_remote

Member
Hello all,
I've posted her a while ago, but lost my log-in, so I'm only a moderate newbie.

I recently found a good deal (via auction) for a used 35mm adapter for my DVX100b. It' s Guerrilla brand, and I got a Nikon Nikkor-S 2.8 to mount on it.

I'm getting pretty fantastic images... but only about 12-18 inches in front of the lens. I can't seem to focus at anything beyond this distance, adjusting the focus on the camera or the lens. I've tried adjusting a few different settings, but are getting zero results.

Any ideas?

Thanks in advance.

R.
 
it's most likely your back focus. meaning , the distance from your ground glass to your 35mm lens is off. Im not sure off the top of my head but it's something like 42mm distance from the two. But double check that, cause 1 mm can throw it off. Or it could be you need more space between your camcorder lens and ground glass. You also want to have you achromat screwed right on your pani lens. thats about all it can be screwing it up. it's actually a very simple setup once you play with it for a while.
 
Hmmm...

Hmmm...

Interesting. After I had trouble screwing the 35mm mount to the longer adapter piece that screws into the camera, the vendor added a filler ring that made the threads on both pieces fit together (don't ask me why the pieces didn't fit together to begin with).

The filler ring is small but adds to the distance between the 35mm lens mount and the rest of the adapter. If only 1mm can throw off the calibration, I'm pretty sure this filler ring fix could be doing it.

Are there no other camera settings that I'm blanking on that would inhibit the focusing?
 
Enumerate the steps you did in mounting your adapter, I'm sure you've researched about the role of backfocus, achromats and the like.
What brand of adapter are you using, do you know the achromat power? What nikon lens are you using?
(the achromat power determines the distance from achromat to your dvx lens)

Providing the steps you did and telling us due diligence you have done can allow members to help much faster.

Even posting a pic of your setup will surely expedite matters.
 
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35mm problem w/pics

35mm problem w/pics

It's a Guerrilla 35mm with a Nikon Nikkor-2 2.8 lens.

DSCF0478.jpg
DSCF0486.jpg
DSCF0484.jpg

I don't know if you guys can see in the third pic where this "filler ring" sits between the adapter and the the lens mount. I'm having issues manipulating pics.

Let me know what you think or if you need other pics.
 
I could be wrong, but seeing that focal plane indicator on your pic, and using a nikon lens, I think you have that adapter inverted. Meaning, the end you attached to your camera is suppose to hold the lens mount.
 
Please confirm if the groundglass position corresponds to that focal plane marker on your adapter tube. If it is, then its very likely your adapter in assembled wrong. Th distance between the nikon mount rim to the groundglass surface is only 46.5 millimeters. The distance from gg to achromat is not an absolute value but depends on achromat power.
 
While I would be relieved (and a little embarrassed) if that were the case, the other end of the adapter in no way fits the camera end.
 
it seemed to be attached to a removable step down ring. Which can be removed by twisting it. Its impossible that its fixed since this adapter is supposed to be used by cameras with smaller ring diameter.
 
Step down ring

Step down ring

Teddybear,

A few hours ago, I removed the step down ring and literally held the lens mount on for some quick testing. With just a few adjustments, I was able to focus at much greater lengths. It looked great.

As I suspected, the distance that the step down ring was adding between the mount and the adapter appears to be the issue. It threw the optic calibration way off.

I'll be testing more tonight and tomorrow. I'll post again tomorrow and let you guys know how it's going. Thanks for the help.
 
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