Formatt-Hitech has a 4x4 Fircrest Ultra that is 24 stops now. I use only F-H filters for my grad nds and nd filters. 24 stops, 100 iso, f/16 or f/22 and you will need a day or two to get an image. Stack it with a 2nd 24 stop and well... I also put the ND gasket on the holder and mount the filter up against that as well, no light leak there. I would also wrap a black out cloth over the entire camera just before you release the shutter. Do post up the picks when you get them
You can also calculate the required exposure assuming linear response as exposure time no filter *2^n where n is the filter factor. Example, say for iso100. f/16 the required exposure time is 1/2 second, then 0.5*2^7.2 = 97 days. At 1/500 sec, = 9.3 hours. So, depending on your goal, a 24 stop may be way too much the 16 stop filter may work for 1/2 second = 9.1 hours. Using Tmax 100 would be like 18.2 hours if the reciprocity function holds where required exposure doubles for pretty much anything 1 minute and longer.
I love the F-H filters, they are truly neutral. Check out BWVision.com for one artist that uses them. Just be sure to seal up camera well prior to exposure.
Hi all,
Great info above, thank you!
I'm wanting to use my 210mm G-Claron (Dagor type) for the long exposures, and am now trying to get the kit together. I want to put the filter behind the lens and within the bellows of the camera but have a few questions...
For those that know the Dagor type G-Claron 210mm, am I correct in thinking that the rear 'filter thread' is 36mm? I've tried to measure it with digital callipers, but I want to confirm before I commit to buying a threaded adaptor for a filter holder system. I know the outside of the rear barrel (if that's the correct term) measures 39mm, so think 36mm seems about right for the thread?
I'm thinking of using the Lee Seven5 system holder, with a 15 stop Pro IRND. I'll need to do something about light spillage out the sides of the filter if I go this way (gaffer tape?) but in principle it should work, although I'm suspicious with a rear lens element so small that the screw in filter holder adapter might introduce some vignetting...
Anyone able to speak to the above, either with regards to using filters with the G-Claron or otherwise?
Thanks again,
Tim
Or, you could just mount it on the front of the lens like 99.9999% of photographers do...
Lachlan.
You miss 100% of the shots you never take. -- Wayne Gretzky
Yes, you can’t do that, however you will create a focus shift and reduce the resolution of the lens by just putting an immaculately clean filter behind the lens. Any defects in filter quality or dust, grease, fingerprints, etc. will further degrade the quality of a lens.
A good rule to follow is to never put a filter inside or behind a lens unless that filter is specifically designed by the lens manufacturer to be placed there!
Lee gel snaps are great for behind the lens, but not sure it’d work for anything that dense... gelatin filters are better for behind the lens because they are so thin you don’t really have to worry about focus shift.
In terms of tape, I use black artists tape because it’s thick enough to be opaque, and easy to remove. I’d be hesitant to use gaff tape because it’s so sticky.
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Why do people bother with a good lens and then spoil it all with either a cheap filter or one put behind the lens?
https://www.bwvision.com/complete-gu...-2016-edition/
Great exposure chart, I recommend the Format Hitech ND filters, I use the slimline screw-ons
Originally Posted by Drew Wiley
Because “sharpness” isn’t the be all end all in photography!! Life(and photography) would be kinda boring if we were all after the same thing...
OP - are you trying to shoot inside or outside? I once tried an interior 24hr exposure with a welding filter - about 14 stops - and portra 400. The neg was very thin with no detail whatsoever in the shadows.
Can you report back once you get some data? It’s good to hear others successes and failures with pushing film to its limit!
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I'm wanting to shoot outdoors, from dawn to dusk; entirety of a days worth of daylight hours.
By my estimation–and it's just that, an estimation–is that a 15 stop ND should do the trick with 400ISO film shot at f45 or 64, perhaps pulled a bit to control the contrast, although I'll do some tests first to confirm that. Will really depend on the light of the day. It's as much for conceptual as aesthetic reasons I want to do this, as I'm trying to build on a long term project that has increasingly become about the light at a particular location. Anyway, it might not work or it might work and not look interesting, but I want to give it a try.
The reason for putting the filter behind the lens was simply because so many people recommended it as a way to help avoid flare as well as light leaks getting in via oblique angles in the filter holder. It's a relatively extreme use case regardless of filter position. I didn't know that putting a filter behind the lens can cause focus shift. That will need to be something to consider. I already have and use a Lee Universal Lens hood with filter slots, perhaps I just start by using that and make sure I tape up the sides of the holder really well. Not sure if there's an adaptor that goes to a thread as small as my G-Claron has, or if a screw in filter holder will introduce vignetting, but there's only one way to find out...
Thanks,
Tim
Because “sharpness” isn’t the be all end all in photography!! Life(and photography) would be kinda boring if we were all after the same thing...
OP - are you trying to shoot inside or outside? I once tried an interior 24hr exposure with a welding filter - about 14 stops - and portra 400. The neg was very thin with no detail whatsoever in the shadows.
Can you report back once you get some data? It’s good to hear others successes and failures with pushing film to its limit!
Sent from my iPhone using Tapatalk
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