Apertures for Zeiss Triple Convertible

**ridax** · 29-Jul-2022, 03:00

Originally Posted by Keith Fleming

....an orange filter to see how well that increases the negative's contrast

I just realized that you probably were referring to the contrast between the different-colored subjects in the negative, not the lens contrast itself (i.e. the contrast in monochromatic subjects that depends on the lens flare). Yes the color-dependent contrast will differ of course, regardless of the lens type.

**Edison** · 29-Jul-2022, 05:53

ridax,

Thanks for the info. I’ll read it a few times. About the filter size. I was wrong and confused series vii lenses with series vii filters. After seeing photos on eBay of series vii to 52mm the size made no sense and now it does- because they’re two different things. I tried a 40.5mm filter just now and my barrel is much smaller. Around 36mm, I’ll have to measure it. But maybe then I can get an adapter so I can use my larger filters I already own. Again, thanks.

Edit: I measured the outer diameter of the lens's threads and it is 36mm. I'm don't know how to determine what filter size this is, I suppose it could be a smaller size. 35.5mm seems the be common enough at B and H. there is no 36mm available. https://www.bhphotovideo.com/c/produ...22_filter.html

**ridax** · 29-Jul-2022, 08:36

~36mm? You may try a standard 35.5mm filter. Charnces are it fits.

**Edison** · 29-Jul-2022, 08:51

Originally Posted by ridax

~36mm? You may try a standard 35.5mm filter. Charnces are it fits.

Thanks for confirmation. I think I'll try out a 35.5mm to 49mm step up adapter and use my Yellow 8.

**David Lindquist** · 29-Jul-2022, 13:41

I have a Zeiss Protar C Set. Based on Harmut Thiele's reference above, the 22 and 29 cm lenses were made circa 1929 and the 35 cm lens circa 1931. The thread mount diameter on these is 40.5 mm, the thread pitch is 40 threads per inch (t.p.i), fitting the set's dial-set Compur. It is my understanding that Deckel used 40 t.p.i. on the dial-set Compurs, the Compound shutters and the later rim-set No. 2 Compur. Reasons for this rather than a metric pitch has, as far as I can tell, been lost in antiquity. When I got this set a few years ago it also included two yellow filters, probably of the same vintage as the lens set; they are like the filters described in my 1933 Zeiss catalogue. One is marked "Carl Zeiss Jena Gelbglas D x 42", the other "Carl Zeiss Jena Gelbglas L x 42". The "D" and "L" refer to "Dark" and "Light", the "42" is the size to slip on the lens. Also included in the lens set is a ring that screws in to the front of the shutter when only a rear lens is mounted, it's of the proper size that the filter will slip on to it.

The Zeiss catalog states of their glass filters: "This material is entirely different from the common yellow glass screens which are still widely sold and which transmit more short-waved light and less long-waved light than is done by our glass, and are hence inferior in both respects." Both my filters look to be in very good condition especially given that they could be 90 years old. I cannot, however, see a difference between the "Dark" and the "Light" one.

I haven't used these filters, rather I use a Linhof filter holder system that takes either 4 x 4 in./ 10 x 10 cm filters or 95 mm screw-in filters. I did make up a fitting that screws in to the shutter's front thread and which holds a 43 mm uv filter to protect the shutter's innards when only a rear lens cell is in place (something that, in fact, I've hardly ever done.)

David

**ridax** · 29-Jul-2022, 22:14

Originally Posted by David Lindquist

<....> made circa 1929 <....> described in my 1933 Zeiss catalogue. <....> The Zeiss catalog states of their glass filters: "This material is entirely different from the common yellow glass screens which are still widely sold and which transmit more short-waved light and less long-waved light than is done by our glass, and are hence inferior in both respects."

Funny enough, those are most probably the early (and new and exotic those days) specimens of MODERN yellow glass filters. The filter I described above was much older, coming from the pre-Protar "Zeiss Anastigmat" era. As your 1931 catalog states, the modern sharp-cut filters are superior in their smaller filter factors for the same degree of spectral correction. The difference in the filter factors / exposure compensation needed is still negligible for panchromatic films but is pretty noticeable for orthochromatic emulsions widely used a century ago.

But the modern red, orange, yellow and the majority of UV-absorbing glasses introduce additional flare into the optical system, while the old amberish Zeiss filter, as well as the modern Wrattens, Tiffens and the yellow-green glass filters do not.

**David Lindquist** · 30-Jul-2022, 11:43

Originally Posted by ridax

Funny enough, those are most probably the early (and new and exotic those days) specimens of MODERN yellow glass filters. The filter I described above was much older, coming from the pre-Protar "Zeiss Anastigmat" era. As your 1931 catalog states, the modern sharp-cut filters are superior in their smaller filter factors for the same degree of spectral correction. The difference in the filter factors / exposure compensation needed is still negligible for panchromatic films but is pretty noticeable for orthochromatic emulsions widely used a century ago.

But the modern red, orange, yellow and the majority of UV-absorbing glasses introduce additional flare into the optical system, while the old amberish Zeiss filter, as well as the modern Wrattens, Tiffens and the yellow-green glass filters do not.

Thank you for this. The 1933 Zeiss catalog I cited can be seen here: https://www.cameraeccentric.com/stat...fs/zeiss_3.pdf The filters are described on page 38 and 39. On my 1934 Zeiss price list the 42 mm filers were $6.00 each.

David

**Edison** · 31-Jul-2022, 21:16

Thanks for everyone’s help, especially to David who had the cheat sheet needed. Here’s a couple shots from yesterday’s party. It is pretty amazing the reaction you get with an older camera. Camera is Korona View 4x5, lens is Zeiss Protar 224mm, Packard shutter, 4s exposure at f/16, no filter. Film is arista.edu 100 (foma) developed in d76 1:1.