360mm Apo Sironar S : filtering the dang thing

[Jarin Blaschke]

Hello everybody:

I've added a 360mm lens to my limited but slowly growing 8x10 kit. It's shipping now. Previously, I was mostly using my 300mm Apo Sironar S, which has a 100mm thread and with which I use a 100-105mm step up ring to use 105mm filters. Embarrassingly, I now have over $1600 invested in 105mm filters, and obviously I would like to use them with the excellent 360mm I just acquired.

The silly thing is that the 360mm Apo Sironar S has a 112mm lens thread. I don't know of any filter made at this size, nor can I find a step down ring from that size to any other on B&H. Does anyone know where I can obtain such a ring, or how I can otherwise use my filters, save the dodgy use of tape on a very fine lens and camera?

Jarin

 

[btaylor]

The folks over at LFPF would probably have some ideas. Surely SK Grimes would be able to make an adapter, although stepping down you could have a vignetting problem, no? Then again I believe you are the cinema field, there are lots of shops in LA that make all manner of special gear. I like Cinema Engineering Co, Richard has a complete machine shop there.

 

[Dennis-B]

Is it possible to use a rear-mounted filter? It looks like the rear barrel is 80mm. Just a thought.

 

[WilmarcoImaging]

Gelatin filters with a filter holder or compendium are an option. The LF site is a good resource for ideas, specific manufacturers, models, etc. Also a step up ring produced by Grimes is a good idea.

 

[DREW WILEY]

Rear mounting a filter would spoil the whole point of selecting an expensive optic like this. So would a gel. The only logical solution is to get a custom-made step-up ring, or else sell the lens and buy a different 360. Stepping down would also be counterproductive because you'll mechanically vignette that wider aperture performance this lens series provides. But since you chose to buy a huge draft horse of a 360, a big saddle simply comes with the territory. The appropriate ring is a simple task for any machine shop; but Grimes is a good place to go.

 

[jim10219]

Can you find a plastic lens cap for it? You could drill out the center, buy a cheap 112mm filter and bust out the glass, and glue the filter ring onto it. Sure it would vignette, but depending on the image circle this beast projects, you may just lose the ability to use some extreme movements that you’d never use. Be warned though, sometimes those cheap filter rings can lock up other filters. There are ways to work them free, and perhaps some cleaning with a wire brush and/or lubricant ahead of time might help.

Or, as Dennis suggests, use a rear mounted filter. They’re more of a pain to deal with, but they work just as well.

 

[Jarin Blaschke]

Alright, looks like Grimes is getting a call tomorrow.

Thanks for all your help everyone. Without a matte box, I don’t think screw-on filters come larger than my 105mms. My hope is that with the somewhat generous coverage of the lens, the 7mm step down on a 112mm front will rarely be a handicap. I do use filters most of the time though.

J

 

[Alan9940]

Rear mounting a filter would spoil the whole point of selecting an expensive optic like this. So would a gel.

I'm curious, why? I've used thin gels on the back of my 6.8/360 Schneider Symmar-S for nearly 40 years and I've never noticed any issues in my negs.

 

[DREW WILEY]

Alan, that kind of argument doesn't even factor ways your images could actually be improved, if necessary, with modern glass filters or a newer design lens. Today, Wratten gels aren't by any means cheap. Outdoors they are highly susceptible to dust and damage. And it all depends on your standard of reproduction. Even high
quality glossy magazine cover images and book images are only modestly enlarged, if at all. Then there is the issue of flare sometimes. All these little things tend to add up. What works fine for one person's range of applications might not be ideal for another's.

 

[Neil Poulsen]

That's a challenge; having a filter thread of 120mm, the 360mm Symmar-S that I had was worse. And, talk about heavy!

My current 355mm G-Claron has a filter thread of 77mm and is much more convenient in both regards.

 

[DREW WILEY]

I have several 360's, including a 360 Fujinon A - the holy grail of 8x10 lenses in my opinion - as well as a 14" Kern Dagor, a 360 Apo Nikkor, and a 360/9 Zeiss tessar. All of them have step-up rings to common 67mm filters.

 

[Mainecoonmaniac]

If you could do it, you can try putting a filter on the back element of the lens. You got a big chunk of glass.

 

[Tom Taylor]

The Cokin X-Pro has a 112mm adapter ring: https://www.bhphotovideo.com/c/product/169219-REG/Cokin_CBX100_X_Pro_Filter_Holder_Requires.html

Thomas

 

[GLS]

Lee make a 112mm adapter ring for their filter systems. You would presumably need to use the 150mm filters and holder to avoid vignetting.

 

[Jarin Blaschke]

Lee make a 112mm adapter ring for their filter systems. You would presumably need to use the 150mm filters and holder to avoid vignetting.

But these filters are gels, no?

J

 

[GLS]

But these filters are gels, no?

J

They do make a whole range of gels (for colour correction mainly), but no, the main filters are either optical grade resin or glass.

 

[JensH]

The silly thing is that the 360mm Apo Sironar S has a 112mm lens thread. I don't know of any filter made at this size,

Hi Jarin,

Here some are offered, B&W - they are not cheap anyway...

https://www.bw-filtershop.de/index....tellerf?custom_f_7[0]=313132206d6d&Itemid=247

As you have a set of fine 105mm filters, I would try to find someone who can make a step-down ring adapting the M105mm to slip-on 80mm and mount the filter backsides.

Best
Jens

 

[Neil Poulsen]

I know what you mean. I had a Symmar S 360mm for quite some time that required filters over 120mm. This lens was both huge and heavy. I now use a 355mm G-Claron.