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ruilourosa
7-Dec-2018, 09:32
Hello

would it be usable to put a 82mm IV scheneider center filter (+1.5) on a 115 6.8 grandagon?

would it be usable to put a 67mm III scheneider center filter (+1.5) on: a 98 6.8 grandagon?, a 75mm wa nikkor, a 55mm apo grandagon?

there are manufacturer´s instructions, i know, and Dan´s paper, but can anyone comment on usability or problems?

Thanks


:cool:

Bob Salomon
7-Dec-2018, 10:03
Should work OK except on the Apo Grandagon.

ruilourosa
7-Dec-2018, 12:09
Thanks!!!

I understand that Rodenstock points towards a +2 filter for 110º lenses ... maybe a 0.5 could be negligible or correctable... any experiences??

Thanks!!!!

Bob Salomon
7-Dec-2018, 12:24
Thanks!!!

I understand that Rodenstock points towards a +2 filter for 110º lenses ... maybe a 0.5 could be negligible or correctable... any experiences??

Thanks!!!!

Yes, use the correct filter, the others will result in a hot spot! Why do you think that Rodenstock went to the time and trouble to make a special one just for the Apo Grandagon lenses?

ruilourosa
7-Dec-2018, 12:36
Humm... manufacturer´s go to the time and trouble because they want to sell... :D

but i will give it a go!!

Bob Salomon
7-Dec-2018, 12:55
Humm... manufacturer´s go to the time and trouble because they want to sell... :D

but i will give it a go!!

They wouldn’t be able to sell the lenses if the regular center filter didn’t correct the fall off from the extreme wide angle lenses. That is called satisfying their customers.

For that matter, the Schneider CF will not correct the other lenses as well as the correct filter will. But, if you are trying to save money, then the difference probably will not be worth it to you. But the Rodenstock ones are more color neutral and will not have the magenta cast in highlights like sunny buildings with bright metal work.

hiend61
7-Dec-2018, 13:12
I have been a long term user of Apo Grandagon 35, 45 and 55mm lenses, and all I can say is that Bob is absolutely right. Center filters for Apo Grandagon lenses have a factor of 2,5x That is OK for 45and 55 apo grandagons, but the 35 has 120º, a huge fall off, and in my opinión based in heavy use for years is that this lens would need an even larger correction. 2,5 is OK with moderate movements, but if you want to reach the limits be prepared to assume fall off even with the 2,5x filter.
Sinar offered a 2x center filter for their Sinaron WE lenses ( Apo Grandagon 45 and 55) this is OK with moderate shift. If you need to reach the limits, the 2,5x centerfilter is mandatory in the case you use chrome film, which is my case. For lenses with an angle of 100 - 105º you can use Schneider, Rodenstock or Heliopan Center filters. My preferred ones are Rodenstock because they are the slimest and most neutral in 58, 67 and 82mm.


They wouldn’t be able to sell the lenses if the regular center filter didn’t correct the fall off from the extreme wide angle lenses. That is called satisfying their customers.

For that matter, the Schneider CF will not correct the other lenses as well as the correct filter will. But, if you are trying to save money, then the difference probably will not be worth it to you. But the Rodenstock ones are more color neutral and will not have the magenta cast in highlights like sunny buildings with bright metal work.

Dan Fromm
7-Dec-2018, 14:05
Center filters for Apo Grandagon lenses have a factor of 2,5x That is OK for 45and 55 apo grandagons, .

The first CFs offered for Apo-Grandagons were 2.5x. They were later replaced by 2.0x CFs.

ruilourosa
7-Dec-2018, 14:46
they were really in trouble!!!! :D

chassis
7-Dec-2018, 18:37
This is a Schneider CF III on a Nikkor SW 75/4.5. It works, it's usable, no problems.

https://www.wilmarcoimaging.com/img/s/v-3/p3144868899-4.jpg (https://www.wilmarcoimaging.com/p46190493/ebb72e423)

Bob Salomon
7-Dec-2018, 19:04
This is a Schneider CF III on a Nikkor SW 75/4.5. It works, it's usable, no problems.

https://www.wilmarcoimaging.com/img/s/v-3/p3144868899-4.jpg (https://www.wilmarcoimaging.com/p46190493/ebb72e423)

But Nikon never made center filters so you had to use other brand ones. That isn’t true for the German lenses!

ruilourosa
9-Dec-2018, 03:23
nothing better than trying!!!

but seems that some are easely intermutable...

maybe wider angles and non super-angulon type designs will be more troublesome...


one question... has anyone tryed to DIY a center filter... glass... petroleum lamp... just wondering...

Dan Fromm
9-Dec-2018, 07:24
maybe wider angles and non super-angulon type designs will be more troublesome...

Wider angles? Rodenstock and Schneider recommend CFs only for lenses that cover at least 100 degrees. None of their lenses covers more than 120 degrees. If you want a wider lens, accumulate your small monetary units until you can afford Rodenstock Pantogonal or a Hypergon with spinning star. The spinning star is a mechanical CF.

If by non-super angulon types you mean classic wide angle lenses with small front elements, well, yes, they are more troublesome because of the difficulty of mounting a modern CF on one. There's an exception. R'stock made a CF for the Pantogonal, a yellow-green thing called Enixantos.

ruilourosa
9-Dec-2018, 08:59
wider angles: 110, 115, 120 degrees... those are the wider of the super angulon type

by non super angulon type i meant super symmar xl ones

by troublesome i meant a higher difficulty to swap between filters and lenses of different brands

Dan Fromm
9-Dec-2018, 11:33
wider angles: 110, 115, 120 degrees... those are the wider of the super angulon type

by non super angulon type i meant super symmar xl ones

by troublesome i meant a higher difficulty to swap between filters and lenses of different brands

If the shoe fits, wear it. What matters is filter mount threading and filter factor.

I don't know whether this https://1drv.ms/b/s!AggQfcczvHGNnBX28ZyoWkE24Tqq is still on line, so here's my copy. Look at the list of lenses that take center filters.

ruilourosa
10-Dec-2018, 05:39
DIY??? no one tryed?? :D

cheers!!!!

Dan Fromm
10-Dec-2018, 06:21
If you want to try, look at the CFs supplied for B&L Metrogons.

ruilourosa
10-Dec-2018, 07:26
I notest that the metrogon center filter does not have a soft transition between the unfiltered area (near the edges) and the start of the ND area... it seems abrupt...

Just for fun: i could use an old uv filter and try to smoke the central spot, i can try with different "smoking" : candles, gas, petroleum... or... maybe i could try other methods... printing digitally? analog veiling?

it´s not a thing i will depend on, but it could be a good thing for experimental things... For ex: making a center filter to substitute the propeller of the hypergon???

I know optical makers spend years and an enourmous amount of math to figure it out... :D

Jac@stafford.net
10-Dec-2018, 08:41
If you want to try, look at the CFs supplied for B&L Metrogons.

I think Corran has an experience with one of those.

There were also some star-like CF filters such as this one: http://www.digoliardi.net/skc/skc-filter-1.jpg
The rectangle in the filter just a reflection of a window in the scene.

ruilourosa
10-Dec-2018, 09:13
Hummmmm!!! it seems doable... but maybe it needs some kind of rotation for evenness? a nd gelatin cut to size in a flower or propeller shape and some rotation??? or a divided exposure with movement in the filter?

the smoking appeals to me... maybe i can give it a go...

Dan Fromm
10-Dec-2018, 09:44
Some of the Metrogon filters appear to be metal sputtered through a mask.

Corran
10-Dec-2018, 12:01
Since Jac brought it up, yes I have a CF for the Metrogon.

It flared a lot even in diffuse light. I cleaned it as much as I could, so it wasn't dirty as far as I could tell. I stopped using it (recently shot some 8x10 slides with the Metrogon even and the fall-off was not noticeable in that situation...but YMMV depending on the photo).

It was also colored so no good for color work but great for b&w! If it didn't flare anyway.

As for the original question, it might be best to use the "intended" CF but a CF designed for a similar lens or FOV with the right size/threads pretty much should work a-ok. I wouldn't hesitate to use my Schneider 3B on my Rodenstock 90mm if need be, because I have it already and it fits the same.

If your goal is to photograph a blank grey wall with perfect even density throughout the entire image with a wide-angle, get the exact CF specified by the manufacturer :rolleyes:.

Dan Fromm
10-Dec-2018, 12:20
If your goal is to photograph a blank grey wall with perfect even density throughout the entire image with a wide-angle, get the exact CF specified by the manufacturer :rolleyes:.

Interesting. The manufacturers don't quite make this claim. And their specs don't support it. For example, at the edge of its field a 35/4.5 Apo Grandy is down four stops from the center @ f/8. With a two stop center filter, the difference between center and edge will be reduced to two stops.

Corran
10-Dec-2018, 12:38
Fair enough Dan, it was more of a joke though :).

ruilourosa
11-Dec-2018, 03:42
I wish someone could give some ideas about constructing a center filter... metal sputtering is not a thing that i easely do...

well i will give a chance to smoking...

Thanks for alll the answers and knowledge

Dan Fromm
11-Dec-2018, 06:37
Not to be a complete idiot or anything, but why do you want to make a CF? Do you have an extreme wide angle lens that no existing CF will fit? Are you poor or broke?

A proposito de metal sputtering, the Metrogon CF has a pattern of small dots, closely spaced near the center, farther apart away from the center. Are you acquainted with silk screen printing?

ruilourosa
11-Dec-2018, 07:08
I like doing things... and a challenge is a good thing!!! i´m a teacher and research is a nice thing!!!

CF´s are expensive and maybe people want to have a viable way to make their own...

silk screening can be a bit coarse... but since it´s so close to the lens...

Drew Wiley
11-Dec-2018, 11:53
Splattered mud or bugs on a windshield? I think that idea has already been tested a few billion times.