Ikoflex infinity focus, and focussing screens

[mskb]

Dear All,

I have a feeling that my Ikoflex IIA is not focusing to infinity. Because the throw of the focus wheel from 48 -> Infinity is small, I want to be sure that this is a genuine concern. I had a few questions. I would greatly appreciate your insights!

1. Is there a good way to make sure of the issue? There is no movement of the focus wheel past infinity, and focusing on clouds feels like I could use "jussst a bit more" movement in the focus wheel. Does trying to focus on stars work? Its been a while since we had clear nights. Any non-star options?

2. Is it possible to read off the distance at which the camera is focused from the Depth of Field scale, printed around the focusing wheel? For example, after fully rotating the focus wheel for focus at infinity, my infinity point in the DOF scale does not ever hit the 'center' mark of the DOF scale, it stops a bit before it, but then I am not sure if the center mark refers to the distance at which we are focused.

3. To make sure the ground glass and focusing screens of the IIA are assembled properly, could you let me know (a) the correct order of the ground glass and the focusing screen, and (b) what sides of the ground glass and focusing screen should face the mirror? I hope I am using the terminology correctly.

Thank you very much!

PS : I had tried the above message on Flickr first. But I soon realized the group has been inactive for over a year. I next tried Photo.net, and then found Photrio to be a lot more active. So apologies if you have seen the above post on Flickr / Photo.net.

 

[koraks]

I'd start by verifying if the ground glass image and the projected image on the film plane are in agreement. You can do this by placing the camera on a tripod, facing a clear structure far away (something on the horizon preferably), opening the back, mounting a piece of glass or transparent plastic with one ground side facing the lens on the film plane and inspecting the projected image with a loupe. This way you're seeing what the film would see and you can verify if the focus mismatch applies to the taking lens as well. It'll narrow down the options and give some direction to the troubleshooting process.

 

[mskb]

Thank you @koraks for the great advice! I will do this.

A good lesson. I should have done this before loading a roll of 120.
Cheers!

 

[lobitar]

Adding to the above valuable advice just the note, that the throw of the focusing wheel on all Ikoflex'es I've seen really IS very small, when compared to Rollei.

 

[Dan Daniel]

The infinity adjustment for the taking lens for the Ikoflex is underneath the side cover. But that usually doesn't go out. I'd look at the focus screen/viewing lens being out of agreement with the taking lens. As said, you start with the taking lens, though. If you don't set that up with a ground glass confirmation, you are dancing in air.

 

[mskb]

Thanks @lobitar and @Dan Daniel for your thoughts! I will get back to you after I do the taking lens focus confirmation.

If any of you can confirm the order and orientation of ground glass & fresnel lens in the viewfinder, it would help to check that as well.

Thanks a lot!

 

[Dan Daniel]

starting at top, surface you can see-

smooth glass surface
ground glass surface
grooved fresnel plastic
smooth plastic.

So grooves and ground meeting in the center.

 

[mskb]

That is very succinct and clear, thank you so much @Dan Daniel !

I will report back as soon as I check this.

Cheers!

 

[mskb]

Hi All,

Both the arrangement of the viewfinder lens/glass, and the focus are in order. It seems to me that the reason I am getting confused is the fresnel lens. I have destroyed a portion of it by cleaning with lens wipes (oh no!). I wish I had seen the following video before; Any thoughts on where I could find a replacement? Any third party working alternatives that you know of?

Cheers!

 

[henryvk]

Depends on how much the camera is worth (to you?). You can get a Chinese focusing screen on eBay for around 20€ (item# 282640795859) or you can spend around 100€ on an Oleson screen.

I've only ever had the former with a split-prism and while they are far from perfect, imo they do the job well enough. You can cut them to the correct size with a pen knife. I've used these as replacements for the Seagull TLR, Lomography Lubitel 166+ and Yashica Mat types and infinity focus was always correct, no need for shimming but ymmv.

 

[mskb]

Depends on how much the camera is worth (to you?). You can get a Chinese focusing screen on eBay for around 20€ (item# 282640795859) or you can spend around 100€ on an Oleson screen.

I've only ever had the former with a split-prism and while they are far from perfect, imo they do the job well enough. You can cut them to the correct size with a pen knife. I've used these as replacements for the Seagull TLR, Lomography Lubitel 166+ and Yashica Mat types and infinity focus was always correct, no need for shimming but ymmv.

@henryvk , thank you very much! I will read about these options, and choose one.