Thanks Gene,
There is a huge thread on this 750mm ApoGerminar, I'll give a try if I find a filter.
(I can may be place the filter after the lens, I hope this is not a strange idea, ... ah these newbies!)
Thanks Gene,
There is a huge thread on this 750mm ApoGerminar, I'll give a try if I find a filter.
(I can may be place the filter after the lens, I hope this is not a strange idea, ... ah these newbies!)
Michael,Originally Posted by Michael Kadillak
I know the Apo Germinar's quite a bit, the 750 as you know comes as f=9 and f=14,5 while the Apo Germinar 1000 comes as barrel lens as 12/1000 and in a Copal 3 as 19/1000 .. this is a bit dim, unless its is a bright day and you are using a Bossscreen. Critical focussing is easier with the f=9 or F=12 also due to the shallower depth of field. Michael, enjoy the long ones .. you have the right countryside over there !
Joerg
Yes, you can place the Neutral density, or for that matter, any filter you want, before or after the lens. It doesn't matter to the film.
If your lens has the filter slot then you could use the gel filters in the slot. I think this would be much better than using a filter on the rear of the lens.
Sudek ambled across my mind one day and took his picture. Only he knows where it is.
David Vickery
Yes it has a slot. Do you have an idea of the type of gel filter to be used, I personally have never used it.
You can get most filters in Gel form. I suggest looking at the website of a big vendor, such as Adorama or B&H and you would have to get a filter larger than the slot probably, and cut it to size with scissors.
Actually, it can matter. If you plan to use a filter behind the lens be sure to focus with the filter in place. Otherwise you will get a focus shift equal to 1/3 the thickness of the filter. This isn't really a problem for gel filters as they are so thin, but can be an issue for glass filters in some situations.
For very long lenses, that have greater depth of focus, it's probably not much of an issue even with a single glass (stacking glass filters behind a lens isn't a very good idea if you can avoid it). But better safe than sorry.
It really starts to be a significant issue with wide angle lenses like the 80mm or 110mm Super Symmar XL that have filter threads on the rear for glass filters. Whenever I use a rear mounted filer on one of these lenses I always make sure to focus with the filter in place.
Kerry
How challenging is it to focus the 750 mm F12 Apo Germinar in a Copal shutter at f 12. Is it still practical for most work. Also how much extension is needed to focus at 4 feet?
Asher
Asher,
no problem to focus that lens .. great performer at longer distances due to coverage..other than tele designs.. and resolution.. although designed for 1:1 .. due to symmetrical design vg from 1:1 to infinity.. this lens and siimilar ones will give you more resolution than you may be able to handle or you may actually need on the larger formats..working with these long ones is fun.. may need an adequate scanner to exploit and manage amount of information of even standard LF formats.
Why would you want to focus at 4 feet ? ..extension is quite a bit .. a shorter focal length will cover and be easier to work with ..
best regards,
joerg
There are extension calculators.
But since you can't find answers to your silly questions yourself, in round figures focusing a 750 mm lens at a subject 48" in front of the lens requires 79" extension. If you meant film-to-subject distance = 48", not possible with a 30" lens.
By the way, why are you fixated on an Apo Germinar? There are other good process lenses with focal lengths around 750 mm that are easier to find and less expensive.
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