Help: infinity focus with 9x12 Unknown beauty

[gimenosaiz]

Hello!

I received an unexpected gif last week :-) A beautifull unnamed 9x12 glass plate camera.
The only reference I can recognize are the manufacturers of the shutter: AGC; and the lens, a Scheneider Radionar 135/4.5 of 1928.
I'd like to use the focus scale as much as possible but I'm sure that it needs to be adjusted. I mean, it seems to have been unmounted and mounted again because the infinity doesn't aims at the camera. So I've tried to adjust it to mount it again correctly but there is something I'm not sure about. I'm trying to find focus using the ground glass that, by the way, it's not cristal clear at all!!!. The question is that I need to extend too much the bellows to find focus at infinity wich is something strange if I compare it with my Pacemaker and its Optar 135/27. And if I use that infinity focus point as a reference, if I try to focus an object at 1 meter the reference in the scale is completly wrong at that distance. The same for 2 meters ... So, the focus scale is not realiable at all.
What do you think?

1.
https://farm1.staticflickr.com/947/40106609520_3fdba07127.jpg (https://flic.kr/p/2475RHA)

2.
https://farm1.staticflickr.com/870/27034729707_93c7d39928.jpg (https://flic.kr/p/HbY4gr)

Thank you in advance !
Cheers
Antonio

[Pere Casals]

The question is that I need to extend too much the bellows to find focus at infinity wich is something strange if I compare it with my Pacemaker and its Optar 135/27.


Antonio,

A 135mm focal is a 135mm focal, so from lens rear nodal point to the image plane you have 135mm, (for distant subjects, of course). The single question is the flange to the rear nodal point distance, but it should not be far from diafragm plane...

I'd replace the GG by a clean one, you can get one for 4x5 (some 18€) at e*ay and make it cut.

Then I would place a measuring tape on the floor and I'd calibrate the focusing scale, using the loupe, I'd stick a label on it and I'd make the new markings.

Saludos,
Pere

[Len Middleton]

Hello!

I'd like to use the focus scale as much as possible but I'm sure that it needs to be adjusted. I mean, it seems to have been unmounted and mounted again because the infinity doesn't aims at the camera. So I've tried to adjust it to mount it again correctly but there is something I'm not sure about. I'm trying to find focus using the ground glass that, by the way, it's not cristal clear at all!!!.
Cheers
Antonio

Antonio,

If the distance from the focal plate (ground glass) to the lens for the two 135mm lenses is close, then maybe the bed scale is not the right one for the lens.

If the lens and bed scale both original to the camera then likely would not be a problem, however if one of them been changed...

Have a look and let us know.

Enjoy,

Len

[Bob Salomon]

Antonio,

A 135mm focal is a 135mm focal, so from lens rear nodal point to the image plane you have 135mm, (for distant subjects, of course). The single question is the flange to the rear nodal point distance, but it should not be far from diafragm plane...

I'd replace the GG by a clean one, you can get one for 4x5 (some 18€) at e*ay and make it cut.

Then I would place a measuring tape on the floor and I'd calibrate the focusing scale, using the loupe, I'd stick a label on it and I'd make the new markings.

Saludos,
Pere

Pere, 135mm is the nominal focal length, not the actual focal length. Any two 135mm lenses, from the same or different manufacturers, will vary +- from that nominal focal length.

[Pere Casals]

Pere, 135mm is the nominal focal length, not the actual focal length. Any two 135mm lenses, from the same or different manufacturers, will vary +- from that nominal focal length.

Thanks for pointing it. Single Radionar in the schneider vintage lens data looks it is the 40mm, it says an effective F of 41mm.

https://www.schneideroptics.com/info/vintage_lens_data/small_format_lenses/radionar/data/2,8-40mm.html

[Steven Tribe]

There is no garantee that 135mm lens is the one that was originally mounted on the camera from new! The early 9x12 folders most often had a F6.8 DAGOR or a copy mounted. As these cameras were used for at least 10 years by the owners, it may have been replaced by an F4.5 lens which came to dominate the market (Like the one mounted on yours!). Typical focal lengths used by DAGORS on 9x12cm were 120 or 125mm, whilst the F4.5 are mostly longer - again like yours.

[Jac@stafford.net]

Antonio,

A 135mm focal is a 135mm focal, so from lens rear nodal point to the image plane you have 135mm, (for distant subjects, of course).

Oh, should our universe be so accurate. Do not mistake nodal point with flange focal distance. For most of our LF cases, focal flange distance is our reference point because it is simple to measure.

[Nodda Duma]

Oh, should our universe be so accurate. Do not mistake nodal point with flange focal distance. For most of our LF cases, focal flange distance is our reference point because it is simple to measure.

Pere is correct, actually. The flange focus distance isn’t the number stamped on the lens.

[Pere Casals]

Oh, should our universe be so accurate. Do not mistake nodal point with flange focal distance. For most of our LF cases, focal flange distance is our reference point because it is simple to measure.

Jac, OP finds the bellows extension abnormal, I was only pointing (post #2) that the bellows draw has to around the (effective) focal, so around 135mm, as this is not a tele or retrofocus design.

[gimenosaiz]

Hello!!

Woow, thank you very much everybody.

My first choice was to extend the bellows 135mm ... +- But, no focus at infinity.
The focal scale was wrongly mounted as I've said.

Although the image in the GG is not very clear because the crystal is quite dim, I think that I get focus at infinity at around 16 cm!!!! (from the rear of the lens to the film plane).
By the way, the GG has the rough surface inside the camera. I think this is correct.

Thank you!
Cheers
Antonio

[MikeMGB]

The camera may be a Ihagee, the front standard is identical to a Ihagee I have. Look inside the case, there may be a name plate attached close to the rear of the bellows.

[Pere Casals]

Although the image in the GG is not very clear because the crystal is quite dim, I think that I get focus at infinity at around 16 cm!!!! (from the rear of the lens to the film plane).


Antonio,

Check the focal (comparing with the Optar's magnification...).

You may have two abnormal things, one is a not working focus scale, the other is a great missmatch from nominal 135mm to effective (around) 160mm focal.

A possibility is that the lens was disassembled for cleaning but later the elements were not placed in the right position or orientation. I'd start by reversing elements, one by one and checking again, or purchasing another radionar (ebay S. Kreuznach Radionar L 2.8/45 on Pronto Shutter Working 12€) to compare elements' position.

Regards

[gimenosaiz]

Antonio,

Check the focal (comparing with the Optar's magnification...).

You may have two abnormal things, one is a not working focus scale, the other is a great missmatch from nominal 135mm to effective (around) 160mm focal.

A possibility is that the lens was disassembled for cleaning but later the elements were not placed in the right position or orientation. I'd start by reversing elements, one by one and checking again, or purchasing another radionar (ebay S. Kreuznach Radionar L 2.8/45 on Pronto Shutter Working 12€) to compare elements' position.

Regards

Hello, Pere!

Thank you again.
There is another scenario: a missing element... The image in the GG is more than acceptable when I get focus, I mean if you take into account the ground glass condition.
By the way, tha Radionar you mention is superwide !!! I'm going to test the camera with film ;-)

Regards!
Antonio

[Pere Casals]

By the way, tha Radionar you mention is superwide !!!


Well, perhaps it is from a 35mm camera...



There is another scenario: a missing element...

In theory it is 3 elements in 3 groups, so you should see 6 reflections if you place it under a lamp, if you only see 4 then there is a missing element

[Len Middleton]

Hello, Pere!
By the way, tha Radionar you mention is superwide !!! I'm going to test the camera with film ;-)
Antonio

Antonio,

The Schneider Radionar lens came in number of different focal lengths including medium format, but the Schneider Vintage lens reference only includes small format and large format, and does not include the Radionar in large format. If you have all the lens element present, I would trust the engraving on the lens with regards to focal length, rather than information from a web site that is not relevant to what you have.

And yes, missing a lens group may result in a longer focal length. In fact the focal length of a single lens group may be so long as to prevent you from achieving infinity focus with that camera.

Hope that helps,

Len

[gimenosaiz]

Well, perhaps it is from a 35mm camera...



In theory it is 3 elements in 3 groups, so you should see 6 reflections if you place it under a lamp, if you only see 4 then there is a missing element

Hello!

Ok, I'll check it!!

Anyway, the real PAIN is the ground glass ... I cannot assure than I'm really focusing .

Thank you!
Antonio

[gimenosaiz]

Antonio,

The Schneider Radionar lens came in number of different focal lengths including medium format, but the Schneider Vintage lens reference only includes small format and large format, and does not include the Radionar in large format. If you have all the lens element present, I would trust the engraving on the lens with regards to focal length, rather than information from a web site that is not relevant to what you have.

And yes, missing a lens group may result in a longer focal length. In fact the focal length of a single lens group may be so long as to prevent you from achieving infinity focus with that camera.

Hope that helps,

Len

Hello!
Thank you very much for the information!

Cheers
Antonio

[Pere Casals]

Anyway, the real PAIN is the ground glass ... I cannot assure than I'm really focusing .



you can grind the frosted side again, with silicon carbide powder, 600 grid. https://www.youtube.com/watch?v=hxC48_sd6BM

[Bob Salomon]

Hello!

Ok, I'll check it!!

Anyway, the real PAIN is the ground glass ... I cannot assure than I'm really focusing .

Thank you!
Antonio

A ground glass is not forever! You can always replace it with a modern one!

[gimenosaiz]

In theory it is 3 elements in 3 groups, so you should see 6 reflections if you place it under a lamp, if you only see 4 then there is a missing element
Hello!

I think that I can see 6 reflections ...

Cheers
Antonio

[gimenosaiz]

you can grind the frosted side again, with silicon carbide powder, 600 grid. https://www.youtube.com/watch?v=hxC48_sd6BM

Hi!
Thank you !

Regards

A ground glass is not forever! You can always replace it with a modern one!
Hello!

Thanks, I think I'll start looking for it ;-)

Regards

[gimenosaiz]

Hello!

I think that the lens has issues.
Look at the pictures: halos, lack of contrast and, blurry edges and corners and a strange swirly bokeh.
These images reminds me of the first photographs I shot with my Primoplan. It had been dismounted and wrongly mounted!

1. https://farm1.staticflickr.com/972/28148259588_e99ac7bc18_c.jpg (https://flic.kr/p/JTnbUu)

2.
https://farm1.staticflickr.com/906/28148257978_bfb3157f68_c.jpg (https://flic.kr/p/JTnbqJ)IBSOR_Fom100_HC110h_037_197 (https://flic.kr/p/JTnbqJ) by Antonio Test (https://www.flickr.com/photos/123541493@N02/), en Flickr

3. Swirly bokeh ???
https://farm1.staticflickr.com/982/28148255108_b752994313_c.jpg (https://flic.kr/p/JTnazf)IBSOR_Fom100_HC110h_037_200 (https://flic.kr/p/JTnazf) by Antonio Test (https://www.flickr.com/photos/123541493@N02/), en Flickr

4. I'm not sure what this artifacts are these:
https://farm1.staticflickr.com/951/28148256478_6970c01963_c.jpg (https://flic.kr/p/JTnaYS)IBSOR_Fom100_HC110h_037_199 (https://flic.kr/p/JTnaYS) by Antonio Test (https://www.flickr.com/photos/123541493@N02/), en Flickr

What do you think??
Thank you!
Cheers

[gimenosaiz]

Hello!

I've dismounted the lens and I've seen that the shim that helps to support the front element was wrongly placed before that element!! This also seemed to force the second element to be mounted upside down. I think I've mounted it correctly now because I think I can focus at infitnity extending the bellows around 137mm !!!
It's close night in Spain, I'll check it tomorrow ;-)

Thanks!
Antonio

[Nodda Duma]

Well done!

-Jason

[Cor]

There are people out there who will love the wrongly mounted lens for its weird effects...;-)...(I am not one of them though, the novelty/weird factor wears quickly for me)

enjoy the camera and lens !

best,

Cor

[Pere Casals]

I like those wild swirls !

Perhaps the lens should be left like it was :)

The swirls point that with the inverted element the entrance pupil (or the exit one, or both) would be limitating aperture when diafragm open enough.

[gimenosaiz]

Well done!

-Jason

Thank you!

I hope it is really ok now ;-)

cheers
Antonio

[gimenosaiz]

There are people out there who will love the wrongly mounted lens for its weird effects...;-)...(I am not one of them though, the novelty/weird factor wears quickly for me)

enjoy the camera and lens !

best,

Cor

Hi!
Jajajaja ... yes, you are right but I'm fine with the AeroEktar and my little Primoplan ;-)

Regards
Antonio

[gimenosaiz]

I like those wild swirls !

Perhaps the lens should be left like it was :)

The swirls point that with the inverted element the entrance pupil (or the exit one, or both) would be limitating aperture when diafragm open enough.

Hi!

I also like swirls ... but I've enough swirly lenses ;

Thank you
Regards
Antonio

[gimenosaiz]

Hello!

It seems that the lens is now ok :-)

1.
https://farm1.staticflickr.com/824/42041706772_e50f8bf5d5_c.jpg (https://flic.kr/p/2745JHj)

2.
https://farm1.staticflickr.com/828/41367597564_26aa6ec5d0_c.jpg (https://flic.kr/p/262vKwL)


My father volunteered for this test :)

Thank you for your help!!!!!

Un abrazo,
Antonio

[Pere Casals]

It looks a pretty capable lens !

I feel this triplet delivers an amazing bokeh !

[gimenosaiz]

It looks a pretty capable lens !

I feel this triplet delivers an amazing bokeh !

Hello!

I think so! I'll shoot some close portraits with a better background to check that bokeh :-)

Thank you!

[Leigh]

I think that I get focus at infinity at around 16 cm!!!! (from the rear of the lens to the film plane).Hi Antonio,

The distance from the rear of the lens to the film is of no significance.
You may find that number on some specifications, but it's meaningless.

The focal length of any lens equals the distance from the rear nodal point to the film when focused at infinity. Unfortunately, there's no easy way to determine where that rear nodal point is.

The number we commonly use is the "flange focal distance", which is the distande from the lensboard to the film when focused at infinity. That's easily measured.

- Leigh

[Ron (Netherlands)]

Nice pictures, great work.
Btw you don't need a new ground glass: just take it out and clean it with kitchen abrasive (like VIM) comes in powder and fluids: it will brighten it up again! - clean the frosted side!