Apertures for Zeiss Triple Convertible

[ridax]

Yes the #8 is well enough to cut the chromatic aberration (CA) off as CA is most prominent in the blue, violet and especially in the UV parts of the spectrum. In theory, an orange or a red filter should be even better but in practice the difference is too small to be noticed.

As for the contrast loss / flare added due to the filter usage, there are two factors at work: the light reflections inside the filter, and the filter material fluorescing under the short-wave radiation that the filter absorbs.

The reflections are removed / diminished in any filter that has a gently sloping absorption curve so that it is not totally transparent in any part of the spectrum but absorbs a bit of the light it is made to transmit (the same way film antihalation layers do). In a sharp-cut filter, nearly 100% of transmitted light is really transmitted - including all the stray light bouncing inside the filter. Glass coating is a remedy for the situation. All modern UV-blocking, yellow, orange and red filters are sharp-cut ones; gray, yellow-green, blue and amber ones are not.

As for the fluorescence - that problem exists in all modern red, orange, yellow and in many UV-blocking GLASS filters (by any manufacturer). It is not present in yellow, orange and red Wrattens and Tiffens that are not made of colored glass (unfortunately, the Tiffen UV filters are not Wrattens in glass; they are just ordinary glass filters, the same as any other manufacturers' UV's). Fluorescence is also not present in yellow-green GLASS filters (again, by any manufacturer).

And so-called 'UV protectors' do not absorb the UV good enough; the longer UV just gets through. A lot of them fluoresce, too. A good example of a quality UV-blocking filter is a multicoated (HMC or HMC Super) Hoya Skylight 1B. It absorbs all the UV; it does not fluoresce; it has an excellent coating. It does not add any flare to the optical system. And its subtle color tint is irrelevant in BW.

[David Lindquist]

So would the lack of VII mean it’s post 1929? I heard earlier that since it’s in mm rather than cm it’s pre-1910.

Looking back at my notes, it looks like the "VII" was dropped from the lens marking in 1928. The highest serial number I recorded having the VII was a 41 cm lens, serial number 874710. Based on Thiele this was made roughly April-May 1928. For the lowest serial number without the "VII" I have 918759, plus a 48 cm lens, serial number 918866 (and three 59 cm examples, serial numbers 918923, 918934 and 918935). Again based on Thiele, these would have been made roughly July-September 1928.

As far as the change from millimeters to centimeters, 1909-1910 is probably a good approximation. Thiele shows some Zeiss lenses made in 1909 as having their focal lengths in centimeters while other lenses with adjacent serial numbers are described in millimeters.

BTW nice work on the filter holder.

David

[Edison]

I'd like to use this lens on my Sinar. Right now it's in a barrel with a thread that I measure to be about 49.5mm. I tried attaching a 49mm filter to the lens board it lives in, but the filter was too small. I looked up copal shutters and 49.5 isn't close to what is available.
#0 #1 #3 #3s
front thread M29.5-0.5 M40-0.75 M58-0.75 M56-0.75

I suppose I could use a step down adapter from 58 to 49.5, but does anyone have a reference to precisely what size thread is on the barrel? I can only find the reverse of what I might need https://www.ebay.com/itm/254192892407

edit: I just measured with a caliper the 49mm filter and it measures 48.6mm so if I'm measuring 49.5 on the barrel, maybe it's a 50mm thread.

[David Lindquist]

Looking at the pictures you posted earlier it looks like this lens screws in to a flange that is attached to the lens board of your Korona. Your simplest solution would probably be to take the flange off that board and mount it to a Sinar board. Rather than mounting the flange on the front it might be possible to use it as a retaining ring on the back of the Sinar board.

The thing is the thread specifications for the mounting threads for shutters, both old and not so old, are out there, e.g. on the skgrimes website. For barrel mounted lenses, especially one this old, this information is not so readily available. There is not only the thread diameter but also the pitch that has to fit. It's possible the pitch isn't metric.

If you want to be able to conveniently switch this lens between the Korona board and the Sinar board I expect skgrimes could make you a new flange. You can decide whether or not it would be worth the price.

David

[Edison]

David, thanks for the response. I might be missing something but The thing is, the Korona has a packard shutter but the Sinar does not have a shutter, so I’m hoping to buy a shutter so I can use it with this lens. If I could get my hands on a Sinar shutter that would be great but they’re not too common and usually out of my price range.

I think getting a copal 3 and asking sk grimes to make an adapter would be the solution. I’m guessing I’d send in the lens and they’d do the rest.

Thanks

[j.e.simmons]

Kumar had a Sinar shutter for sale here a few days ago at a quite reasonable price.

[Edison]

Kumar had a Sinar shutter for sale here a few days ago at a quite reasonable price.

...found it. While it's a competitive price, it's still out of my budget. Thanks for the suggestion!

[Bernice Loui]

If the Packard shutter is working ok with this lens on the Korona camera, there is little reasons to change. Continue to use that set up as is.. Going to a Copal shutter for this lens will likely equal the cost of a Sinar shutter. Once the cost of a GOOD copal# 3 shutter and work done by SK Grimes is added up, the overall cost can equal or exceed the cost of a good Sinar shutter and all that is done with the Copal shutter with this lens is not transferable to another lens.

Taking the Sinar with Sinar shutter route allows using virtually any lens in barrel from microscope objectives to truly large lenses like a 480mm f4.5 Xenar.


Not just the shutter, Sinar being modular view camera system has few if any limits on camera and bellows extension further removing camera limitations to support lenses required for a given image goal.

Sinar filter holder works with any lens up to about 90mm outside diameter with 105mm threaded and smaller to 4x4/100x100mm square or series 9 filters.


For larger diameter lenses, Sinar has a 125mm square filter system.

It all depends on your specific needs. If the current outfit of Packard shutter, lens, filter holder works for your needs, why change this?
If not, investing in the Sinar system could be the far better choice to meet current and most any image making needs in the future.


Bernice

...found it. While it's a competitive price, it's still out of my budget. Thanks for the suggestion!

[Edison]

Bernice- all true. The thing is i want to take portraits with the 224 (longest I have for the Sinar is 150) and my daily camera is the Sinar so I’d like more speed options than 1/25 for portraits and if I’m out hiking I’d like to have the longer lens. But yes it’s better just to get a 210 for less money. I initially was hoping to find an older copal 3 for say $75 and adapt the lens to it. But what will really be needed is far more like you say.

I’d love a Sinar shutter and I keep my eye out for one but I just can’t justify $500+ for this right now.

Thanks for a voice a reason.

[Bernice Loui]

75 U$D Copal# 3 shutter would likely need work adding to the cost of the Copal# 3 shutter. Typical known good ones are 200 U$D unless the Copal# 3 is canalized from a lens. Then add the cost of custom work to get lens and more fitted to the target camera.

Seems not too long ago when Sinar mechanical shutters were not desirable or priced what they are today. It does appear more than a few view camera folks have figured out and decided Sinar shutters work good with barrel lenses of many varieties.. IMO, they are a worthy spendy if you're into the Sinar system. They still appear for less than what appears to be the current market value of 500 U$D. Anyone paying that much for one needs to have a black version of the Sinar cable release. These are the preferred version of cable release, the chrome/bare metal version has more stretch during shutter cycling and less desirable. Replacement cable is offered by Silvestri (code CR4870), not tried this cable release yet.. but appears good enough.
http://www.silvestricamera.com/cablerelease.html

Best to wait and then pounce on a good Sinar shutter as they become available. As with all mechanical shutters, the to be owned Sinar shutter could need service before it is known good. They are remarkably robust and designed/built to be cycled thousands of times as it was common to expose piles of film per day when these were in production.


Bernice

I initially was hoping to find an older copal 3 for say $75 and adapt the lens to it. But what will really be needed is far more like you say.

I’d love a Sinar shutter and I keep my eye out for one but I just can’t justify $500+ for this right now.