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NEX-5 and infinity focus. A question for you.

sebboh

New member
On the subject of adjusting adapters, I just got an RJ M39-NEX adapter and the lens ends up offset rotationally. I.e., the normal top position of the lens is about 30 degrees to the left. Is there a way to adjust the adapter to allow the lens to return to the top position?

Cheers,
yes: the RJ adapter is made of two pieces, an outer black aluminum piece and an inner chromed brass piece that sits inside. the inner piece is held in place by 3 set screws that can be seen inset around the the outer ring of the adapter. if you loosen these screws the inner ring can be rotated. you could do this with the lens mounted to the adapter to make alignment easy or you could mark on the adapter the distance you want to rotate the inner m39 threads and then remove the lens for realignment.
 

simonclivehughes

Active member
yes: the RJ adapter is made of two pieces, an outer black aluminum piece and an inner chromed brass piece that sits inside. the inner piece is held in place by 3 set screws that can be seen inset around the the outer ring of the adapter. if you loosen these screws the inner ring can be rotated. you could do this with the lens mounted to the adapter to make alignment easy or you could mark on the adapter the distance you want to rotate the inner m39 threads and then remove the lens for realignment.
Sebboh,

Thanks, I'd seen the screws and had assumed that might allow it, but it's nice to have the confirmation.

Thanks,
 

simonclivehughes

Active member

sebboh

New member
My jinfinance adapter doesn't have that gap on it.
is it an m-mount adapter (not ltm or anything else)? i've heard jinfinance is actually a few different manufacturers so it is possible some are made differently than others or that the design has evolved.
 

barjohn

New member
I have a question that i hope someone knows an answer. When shooting in "Anti Blur" or "Hand Held Twilight" using MF, as soon as you press the MF assist button it places the area under magnification at the far upper left corner rather than the center of the frame. I can't seem to find a way to have it default to the center instead of the upper left corner. Anyone else have this experience and if so did you find a solution?
 

sebboh

New member
I have a question that i hope someone knows an answer. When shooting in "Anti Blur" or "Hand Held Twilight" using MF, as soon as you press the MF assist button it places the area under magnification at the far upper left corner rather than the center of the frame. I can't seem to find a way to have it default to the center instead of the upper left corner. Anyone else have this experience and if so did you find a solution?
mine starts in the center of the frame in both those modes. i believe it depends on what type of autofocus mode the camera was in last (center, auto, moveable single point, etc).
 

barjohn

New member
It doesn't seem to make any difference what focus mode I have set prior. I am stumped!

I just discovered that if in MF mode with a manual lens it does start in the center but if in DMF mode with either manual or AF lens, when MF assist is initiated either by the button push with manual lenses or the turning of the focus ring on AF lenses it starts in the upper left corner.
 

sebboh

New member
It doesn't seem to make any difference what focus mode I have set prior. I am stumped!

I just discovered that if in MF mode with a manual lens it does start in the center but if in DMF mode with either manual or AF lens, when MF assist is initiated either by the button push with manual lenses or the turning of the focus ring on AF lenses it starts in the upper left corner.
mine behaves the same way, didn't notice since i'm always in MF mode lately. there are some autofocus modes that will produce the same behavior (focus assist in the top left corner) in all shooting modes when you mount a manual focus lens.
 

barjohn

New member
I'm guessing this must be a firmware bug. Anyone that has an in with SOny, you might let them know about this bug. It really makes it slow to use the DMF mode when you have to move the focus point to the center of the frame each time before you shoot or conversely if you will be switching back and forth between manual focus lenses and the NEX lenses you have to change the focus mode first. Otherwise you could leave it in DMF for both.
 

simonclivehughes

Active member
may i recommend shimming your adapter till you have infinity? the best method i've found to do this is to fold up a sheet of tin foil a number of times and then cut out a ring from the folded tin foil that matches the interior of the adapter. place the stack of tin foil rings in between the part of the adapter that connects to the lens and the rest of the adapter. check infinity focus. hopefully it now no longer reaches infinity (if it still focuses past infinity you need more tin foil rings). take out the tin foil rings one at a time checking infinity focus each time till it is dead on.
If I may, another question on this to clarify...

Do you place the foil shims on the inside of the adapter? Is the object to push the lens away from the body/adapter combo slightly so the lens can reach infinity focus fully racked out?

I need to do this for several lens/adapter combos so I want to be sure of the methodology.

Cheers,
 

barjohn

New member
You normally, remove the 4 screws that hold the lens mount to the adapter and place the shim between it and the adapter and screw the 4 screws back in. We are talking about very small increments. The thickness of a piece of paper or heavy duty aluminum foil. It sure would be nice if the vendors offered pre-machines shims in metal that one could try until the right thickness was found. It has the effect of moving the lens slightly further out from the sensor. If you have a micrometer you could measure the required thickness by visually focusing on a distant object (infinity) and measuring the lens end to fixed portion of lens, then mechanically setting lens to infinity and remeasuring and taking the difference between the two readings.
 

barjohn

New member
I now have my infinity focus spot on but it was not easy. I purchased four 1/8" retaining rings-External Copper Plated at Lowes. They are .25mm thick. As it turns out that is slightly too thick but it was the thinest smallest I could find. I then used my Dremel tool to grind away some of the metal from the back of the flange at each of the screw hole locations. I placed a retaining ring at each screw hole, carefully lowered the ring in place and screwed the 4 screws in slowly tightening but not too tight and testing how smoothly the lens turned and locked. I then took pictures at infinity and compared them to pictures I had taken of the same subject when I manually focused for infinity prior to any modification. I took shots at f2.8 and f5.6. It took several iterations of removing the ring, grinding some more metal off, reassembling and testing again. Before the modifications infinity focus showed 10' on the lens barrel and now it shows infinity.

I almost thought I was there when I was getting sharp images at 5.6 and slightly softer images at f2.8 but further tweaking and comparison with shots taken when it would focus past infinity convinced me I wasn't quite there and sure enough, further tweaks got me right on so at f2.8 it looks very sharp just like at f5.6 for the same distant object.
 
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