Jump to content


Photo

Adjusting focus of Eyemo lens?


  • Please log in to reply
17 replies to this topic

#1 Ben Syverson

Ben Syverson
  • Basic Members
  • PipPip
  • 98 posts
  • Other

Posted 17 March 2010 - 06:43 PM

I shot a test roll on a newly acquired Eyemo, and it came back slightly out of focus. Investigating, I found that the flange distance was 100% correct (1.5000"), but that the lens itself (B&H 50mm f/2.8) was close focusing by a pretty large amount. In fact, it cannot achieve infinity focus in the mount.

Using a piece of diffusion material as a ground glass, I could see pretty clearly that a subject that was 4' away would be in focus when the lens was set to just past 5'.

So, does anyone have any advice or experience that could help? My theory is that at some point in its 70 year life, it must have been adjusted incorrectly. If there's an easy way to readjust it, I would love to do it and give this old lens a second life.
  • 0

#2 Bernie O'Doherty

Bernie O'Doherty
  • Sustaining Members
  • 232 posts
  • Other
  • Newark Valley, NY

Posted 18 March 2010 - 10:31 AM

Hi Ben, The problem with trying to do this yourself, is that, if you loosen the wrong screws and undo and separate the lens threads, it can be difficult to reassemble properly. Missing a thread entry point, which has been mated exactly to it's counterpart for 50 years,will mean a tight and rough focus feel.
There must be someone around that you could trust to do this. Better that than raising your blood pressure, using new cuss words, and wanting to throw the lens in the nearest ocean.
Good luck.
  • 0

#3 Ben Syverson

Ben Syverson
  • Basic Members
  • PipPip
  • 98 posts
  • Other

Posted 18 March 2010 - 10:59 AM

Ha, great advice Bernie. :) Thanks. I think I will talk to one of the rental houses in-town and see if they have any experience adjusting these things.
  • 0

#4 Charlie Peich

Charlie Peich
  • Basic Members
  • PipPipPip
  • 238 posts
  • Cinematographer
  • Chicago

Posted 18 March 2010 - 01:28 PM

I shot a test roll on a newly acquired Eyemo, and it came back slightly out of focus. Investigating, I found that the flange distance was 100% correct (1.5000"), but that the lens itself (B&H 50mm f/2.8) was close focusing by a pretty large amount. In fact, it cannot achieve infinity focus in the mount.


What model camera is it, single lens, "spider" turret, or the compact turret?

The Eyemo M model required a "Eyemo type C" mount. I can't recall if that was because of flange depth differences or not. The repair book I have doesn't list the M model.

There was a color code on the lenses in the form of 3 dots. I think that helped differentiate the mounts. Mostly used/found in military cameras.



Posted Image
  • 0

#5 Ben Syverson

Ben Syverson
  • Basic Members
  • PipPip
  • 98 posts
  • Other

Posted 18 March 2010 - 01:45 PM

Charlie, it's an A4 military style (single lens, full/silent aperture). I have the Air Force repair manual for the camera, but it doesn't have any info on adjusting the lenses.
  • 0

#6 Ben Syverson

Ben Syverson
  • Basic Members
  • PipPip
  • 98 posts
  • Other

Posted 18 March 2010 - 02:22 PM

It occurs to me now that perhaps the lens and camera are completely mismatched; maybe this lens is designed for a turret camera? The lens itself has "1940" stamped on the mount. Here are some pictures which may help.

Attached Images

  • eyemo_body.jpg
  • eyemo_lens_side.jpg
  • eyemo_lens.jpg
  • eyemo_tag.jpg

  • 0

#7 Ben Syverson

Ben Syverson
  • Basic Members
  • PipPip
  • 98 posts
  • Other

Posted 18 March 2010 - 02:38 PM

Here is a scan of a representative frame downsized from 4K to 1440, showing the focusing error... Her eyes are exactly 4' from the film plane and the camera is set to 4'.

Attached Images

  • eyemo_1440.jpg

  • 0

#8 Charlie Peich

Charlie Peich
  • Basic Members
  • PipPipPip
  • 238 posts
  • Cinematographer
  • Chicago

Posted 18 March 2010 - 02:39 PM

Charlie, it's an A4 military style (single lens, full/silent aperture). I have the Air Force repair manual for the camera, but it doesn't have any info on adjusting the lenses.



Ben,

I have the Army version, similar manual, but no lens adjusting, that was handled back at the main depot.

Which lens do you have? Have you tried other lenses? It may be cheaper to buy other lenses.

It will be hard to find a tech with a collimator or projector with the Eyemo mount. Alan Gordon ended up with the Eyemo / Filmo tools and parts when Bell & Howell closed their film manufacturing business. They sold off the Filmo line several years ago.

Paul Duclos might be able to help.
  • 0

#9 Ben Syverson

Ben Syverson
  • Basic Members
  • PipPip
  • 98 posts
  • Other

Posted 18 March 2010 - 02:55 PM

Charlie, thank you so much. I've emailed Paul.

I agree that it may be cheaper to simply buy another lens... If I go down that route, I may try to create a nondestructive adapter for MF lenses rather than chase after a Eyemo lens in shooting condition.
  • 0

#10 Charlie Peich

Charlie Peich
  • Basic Members
  • PipPipPip
  • 238 posts
  • Cinematographer
  • Chicago

Posted 18 March 2010 - 03:27 PM

I made my post without seeing your photos.

Unless you want to restore that lens for the period look of that lens with it's flaws and all, I would look for another lens and try that 1st.

They show up on e-bay....

http://cgi.ebay.com/...4#ht_713wt_1133

search eyemo, there are several lenses listed right now.
  • 0

#11 John Sprung

John Sprung
  • Sustaining Members
  • 4635 posts
  • Other

Posted 18 March 2010 - 03:33 PM

If you're in LA, try Clairmont. They have an optical shop and a machine shop, and do a lot of work on their own eyemo crash cameras. Of course, they mostly put PL's on them.



-- J.S.
  • 0

#12 Ben Syverson

Ben Syverson
  • Basic Members
  • PipPip
  • 98 posts
  • Other

Posted 18 March 2010 - 03:46 PM

I'm in Chicago, so there are not as many options repair-wise.

Charlie, I've been keeping my eye out, but many of the lenses, such as the one you linked to, are fixed-focus. There is one focusing 50mm on eBay right now, but it's $300 and I don't see f/stop markings on it. I'm a little nervous to pull the trigger on another 70-80 year old lens... Maybe I'll post a wanted ad here.
  • 0

#13 John Sprung

John Sprung
  • Sustaining Members
  • 4635 posts
  • Other

Posted 18 March 2010 - 04:22 PM

I'm in Chicago, ....


In that case, the guy to ask is Tom Fletcher. If there's anybody in Chicago who works on lenses, he'll know:

Fletcher Camera & Lenses - Chicago
1000 N. North Branch Street
Chicago, IL 60642
312-932-2700
312-932-2799 Fax
General - frontdesk@fletch.com
Rental - rental@fletch.com
Sports - sports@fletch.com





-- J.S.
  • 0

#14 Charlie Peich

Charlie Peich
  • Basic Members
  • PipPipPip
  • 238 posts
  • Cinematographer
  • Chicago

Posted 20 March 2010 - 11:49 AM

Ben,
Here's a thread on Eyemo lenses

http://www.cinematog...showtopic=11379
  • 0

#15 Ben Syverson

Ben Syverson
  • Basic Members
  • PipPip
  • 98 posts
  • Other

Posted 20 March 2010 - 01:18 PM

Thanks Charlie!

Now I just need to track down a 50mm Miltar lens. Just the other week I let one slip on eBay. Foolish!
  • 0

#16 Ben Syverson

Ben Syverson
  • Basic Members
  • PipPip
  • 98 posts
  • Other

Posted 20 March 2010 - 01:36 PM

BTW, in the other thread, someone mentioned that some wide and medium Eymax lenses were deliberately short focused to increase depth of field for shots focused at infinity. In other words, "infinity" on the lens is actually a hyperfocal distance for f/16 or something.

So I'm thinking more and more that my lens IS correctly adjusted. It's just that the scale on the lens is not meant to directly correlate to where it's focusing (!).
  • 0

#17 Charlie Peich

Charlie Peich
  • Basic Members
  • PipPipPip
  • 238 posts
  • Cinematographer
  • Chicago

Posted 20 March 2010 - 06:30 PM

So I'm thinking more and more that my lens IS correctly adjusted. It's just that the scale on the lens is not meant to directly correlate to where it's focusing (!).


Ben,
Naaaaa, it's off. I have the same lens, but older, sn-313547 vs your sn-371803. On my lens the aperture ring is silver. My lens is uncoated. Perhaps the black aperture ring on your lens means the new "coated" version of the lens ??.

I just checked my lens, and it comes up on infinity and at 3 ft.

If the lens is set at the 4 ft mark on the focus scale, then everything that is 4 ft from the film should be sharp. You shouldn't have to do any math to figure it out! If the image on the film is soft, then the flange depth is off, or the collimation of the lens is off, or both!

How I was able to check my lens?

I have a Eyemo 71QM (Army/Air Force designation A-7). It has the "Direct through-the-lens prismatic focusing magnifier on the right hand side of the camera."

Posted Image

The ground glass is the same flange depth as the lens mount. I do have the 2 Cooke lenses as shown in the picture, the 2" that's in front of the finder, and the 1" that's at the top of the spider turret. Both uncoated.

You're looking for the Militar version of the 50mm. The 1st version (older) of the Militars were "black" barrels and were coated. The last version or newest, had gray barrels, supposedly the best of the Militar line. I did find a gray set of Militars 25mm, 50mm, 75mm, 100mm, & 152mm, they came with a KF-2(1) camera set.

The "Bomb Spotter" camera was just that, the camera that was in a bomber to record the bomb hits. They usually were FIXED focus lenses, (who had time to focus when the bombs were going off?) with the Eymax 6"/152mm f4.5 or the Eymax 10"/254mm f4.5 lens being the most popular.

Any Eyemo lens you get will need some work, all lens surfaces need cleaning and all mechanics need lubing. It all depends what you plan on doing with the camera.

I set out to get a Eyemo and lenses from that period for the look. I wanted a set of uncoated lenses and a set of coated lenses.... early lens designs with all the flaws and flares. I had no desire to put a PL mount on the cameras, I just wanted the look of the camera and lenses from the period. Wind it up and shoot like they did back then. I ended up with 5 Eyemos and a bunch of lenses, some of them worth cleaning and lubing, some were junk, or would cost a lot to restore. Art vs cost.

BTW, you put a frame grab on one of your posts, how was the image registration your camera? Did you use FilmWorkers for the transfer?

Do you want to try out a 50mm uncoated lens?

Charlie
  • 0

#18 Ben Syverson

Ben Syverson
  • Basic Members
  • PipPip
  • 98 posts
  • Other

Posted 20 March 2010 - 07:20 PM

Charlie,

That 71QM is pretty fantastic! Having been spoiled by large format still photography, focusing by tape measure is an adjustment to say the least.

Like you, I'm more interested in the authentic Eyemo "look" than hot-rodding them with crazy mounts. I actually want to do a series of "moving portraits" -- sort of like Warhol's screen tests, but shorter and a bit more restrained. I've even been toying with the idea of flipping the camera and doing them in portrait orientation. So while I need to be able to get the subject in focus, I don't need the crazy sharpness of a modern lens. In fact, an uncoated triplet will probably save me on ProMist costs!

Anyway, that's a long way of saying "yes," I would love to try out an uncoated 50! :)

The scan I posted was a snip from the head of that test roll -- I just threw it into my Nikon V ED. Once I get my DIY scanner set up, I'll know a lot more about the registration. So far it looks pretty steady, but that's just based on comparing the size of the framelines with a loupe.
  • 0


Tai Audio

Gamma Ray Digital Inc

Opal

Abel Cine

CineTape

Broadcast Solutions Inc

FJS International, LLC

Willys Widgets

CineLab

rebotnix Technologies

Glidecam

Media Blackout - Custom Cables and AKS

Paralinx LLC

Rig Wheels Passport

Technodolly

Ritter Battery

Visual Products

The Slider

Wooden Camera

Metropolis Post

Aerial Filmworks

Wooden Camera

Aerial Filmworks

Glidecam

Abel Cine

Broadcast Solutions Inc

Technodolly

Rig Wheels Passport

Media Blackout - Custom Cables and AKS

Opal

Metropolis Post

Tai Audio

CineTape

rebotnix Technologies

Visual Products

Ritter Battery

Gamma Ray Digital Inc

CineLab

FJS International, LLC

Paralinx LLC

The Slider

Willys Widgets