Folder distance scale origin point

[SalveSlog]

Instructions for the Watameter acessory rangefinder clearly states that when taking closeups, you have to measure to the center of the lens. I would think this was usual practice until interchangeable lenses became the standard on slrs? Then the filmplane became a better priciple?
http://mercurycamera.com/wp-content/uploads/2017/12/watameter-rangefinder-instructions.pdf

 

[bernard_L]

Instructions for the Watameter

Thank you for the info and for the manual. As it happens I also have a Watameter to keep company to the Voigtlander distance meter.

 

[AgX]

Instructions for the Watameter acessory rangefinder clearly states that when taking closeups, you have to measure to the center of the lens. I would think this was usual practice until interchangeable lenses became the standard on slrs? Then the filmplane became a better priciple?
http://mercurycamera.com/wp-content/uploads/2017/12/watameter-rangefinder-instructions.pdf

-) close-ups with a finder camera (at least within the distance range offered by the Watamater Super accessory rangfinder) were beyond the focusing range of the respective lenses.
Close-up then meant using an additional close-up lens.
As with these the object has to be put in the focal point of the close-up lens and the camera-lens set at infinity, the only distance information one got thus was the focal length of that close-up lens. Thus with close-ups the focusing reference point ALWAYS was that lens at the front.

(And still is, unless using a close-up lens with the ability to focus on a ground screen, which yields more precision and the possibility to focus even closer, by using the camera's helicoid, without any chart.)

-) I do not know for sure what in the past the focus reference point of finder cameras was, it would have been academic though in most cases.
However, the Watamater manual indicates that the focusing scales on the cameras were referring to the front of the lens.

 

[bernard_L]

Close-up then meant using an additional close-up lens.

What you state about the proper distance setting when using an additional lens is correct. However, extending that to the distance scale of the camera itself is your interpretation (resorting to the special properties of the Watameter Super). The manual for the Watameter rangefinder is, however, quite clear:

In the original document, the caption (just above) "Watameter Super" belongs to the figure of that model, above left. The excerpt that I quote is general.

It would have been academic though in most cases.

Using: http://www.dofmaster.com/doftable.html, 6x6cm format, 80mm focal length, at 1m distance, the DOF becomes larger than the 80mm (approx) distance between lens and film at apertures f/16 and smaller. And even so, given the ever-present random errors, and the actual depth of the subject itself, one would rather not "spend" all the margin in one avoidable systematic error.
For me this is far from an academic question. I try to "carry MF quality in my pocket", meaning a good folding rather than a MF SLR; and I don't want to be confined to far-away landscapes. Before someone makes that comment, yes, a TLR (Rollei*, Yashica, etc) is relatively light, but I already have a C220 and too many cameras in general.

 

[AgX]

"The distance setting of your camera counts from the lens level." Which I read as reference to the distance scale of the lens barrel.

However, in the context of what I pointed out above such reference makes no sense. Yes, likely the people from Wata just meant the focal length of the close-up lens. (However in the graphic that distance is related to center of the barrel...). Anyway, the authors of that manual were likely Germans and thus as ignorant on English as I am.


So, in context of the actual topic of this thread we lost Wata as witness.

 

[Alex Varas]

I have done several collimation of folding cameras, some of them using a ground glass if I knew exactly where the film was placed when closing the back, if I was unsure I used the DSLR way.
I have one 120 technical film with an X draw in the emulsion side, at the same point I cut out a circle on the back paper, I load the film as usual and with the red window I position the film on that spot.
Now with the camera on T or B I put the DSLR (http://elekm.net/zeiss-ikon/repair/collimate/) as said in Mike's tutorial, but in my case I use a film loaded using the same back film plane from the camera to find out the proper distance, for helping to see the X drawn I put a flashlight at the back of the folding red window so it will be visible.
If you need more assistance let me know and I will do a set up at home of how I do it.

 

[AgX]

So you collimate your cameras not on a glass plate on the guides which might turn out a virtual collimation so to say, but in the real-world location of the flimsy film.

 

[Alex Varas]

So you collimate your cameras not on a glass plate on the guides which might turn out a virtual collimation so to say, but in the real-world location of the flimsy film.

The first approach I do is the rails were the film should go, if after the first test doesn’t work I go for the second I described, normally everything is fine after that.

 

[bernard_L]

I have done several collimation of folding cameras, some of them using a ground glass if I knew exactly where the film was placed when closing the back, if I was unsure I used the DSLR way.
I have one 120 technical film with an X draw in the emulsion side, at the same point I cut out a circle on the back paper, I load the film as usual and with the red window I position the film on that spot.
Now with the camera on T or B I put the DSLR (http://elekm.net/zeiss-ikon/repair/collimate/) as said in Mike's tutorial, but in my case I use a film loaded using the same back film plane from the camera to find out the proper distance, for helping to see the X drawn I put a flashlight at the back of the folding red window so it will be visible.
If you need more assistance let me know and I will do a set up at home of how I do it.

Interesting agreement. That is just what I recommended yesterday to the owner of a Nettar in that post:
https://www.photrio.com/forum/threa...much-of-my-nettar-515-16.167101/#post-2174450
Your setup is even more realistic than mine, because you have the paper in place (with hole) although I would bet that the springs of the pressure plate can adjust to the missing paper and press the film correctly.

 

[Alex Varas]

Interesting agreement. That is just what I recommended yesterday to the owner of a Nettar in that post:
https://www.photrio.com/forum/threa...much-of-my-nettar-515-16.167101/#post-2174450
Your setup is even more realistic than mine, because you have the paper in place (with hole) although I would bet that the springs of the pressure plate can adjust to the missing paper and press the film correctly.

This can be done on every 6x6 with red window, 6x9 and 6x4.5 I use old CD and cut out the exact dimension of the back plane (each camera is different) leaving the CD cut out form pressing the same technical film but this time with the open back (because the red windows aren't aligned with the DSLR) and with two rubber bands and some extra for keep the CD on place I do the same operation.

 

[Alex Varas]

Not my intention to duplicate but a link would be placed anyway.

https://flic.kr/s/aHsmxQMU6j

That's how I just did a Hapo 66-E collimation, lets see tomorrow for final checking

 

[Deleted member 88956]

FWIW, I have a Zeiss Super Ikonta III that had a very similar issue when I ran the first test roll through it. I checked focus using a small piece of ground glass that I made; this camera has obvious "rails" that the film rides on. I checked rangefinder accuracy using an external rangefinder and via tape measure, and it was good. Long story short, I sent it to Ken Ruth (he's retired now) and it turns out that the entire front shutter/lens assembly was not parallel or otherwise out-a-whack with the film plane. Took six months to get it back, but it now focuses exactly where I set it via the rangefinder!

This is a common problem with majority of folders. Some were built better to withstand folding/unfolding process, in some front assembly had to be positioned as instructed (often set on infinity) to ensure enough space is available for all pieces to fold into without exerting pressure on anything, some were built so badly that you can feel how much the whole set up goes out of alignment even with very smallest pressure. Over the years things get permanently out of wack, in some cases you can easily see lack of parallelism just by eyeballing from the side. Once optical axis isn't perpendicular to film plane, the focus effect is same as in intended (or not so much) use of view camera movements.

The problems in fixing such issues is mostly from strut design with most pieces being of stamped steel and while sufficiently rigid, once bent ever so slightly (and given geometries of these designs, very little is needed to loose intended alignment) they are even more resistant to getting them back in original shape (often impossible).

Bottom line is that if a folder does not fold easily back in, something is not correct. The process should be nearly effortless. Bellows often are a problem here, as it only takes a few careless operations to develop new unintended creases which in turn prevent them from folding as designed.