ARCA ground glass focussing problem?

[marschp]

Hi - I recently traded in my used Toyo 45A for a new Arca Swiss F 4x5 outfit (including the standard Arca gg+fresnel. I'm very pleased with the Arca and it outperforms the Toyo in all respects except one - the ground glass. Compared to the gg on the Toyo the gg on the Arca is darker, with a less even image brightness, and more difficult to focus - in particular when focusing with a 4x lupe (the same lupe I used on the Toyo) the image just doesn't seem to snap into focus the way it did on the Toyo. All these comments are based on a 150mm Rodenstock S lens with the aperture wide open.

Anyone got any suggestions?

One idea I thought of is to pick up a used Toyo gg on ebay and install it into the Arca, but I don't know if this is possible/easy? Does anyone know if this is a straightforward process.

Alternatively...

...I've thought about going for one of the well known replacement screens but on other threads I've read that the Arca gg is supposed to be quite good and that a brighter replacement screen will not actually produce much improvement over the Arca standard screen - can anyone verify this? of has anyone else replaced their standard arca gg with a brightscreen, or beattie, or ss etc.?

Thanks in advance. Paul.

[Pete Roody]

I use several Arca's and have always found the gg to be equal or better than other makes. The Arca works well (for me) with all focal lengths. I have tried Beatties on other cameras and the Arca system is clearly superior. I have never used a Toyo camera so I can't comment on how good their gg is.

Arca places the fresnel on the lens side (inside) and the gg outside. If you just replace th gg, you will not loose the focus plane. If you replace the fresnel, it must be the same thickness as Arca's.

I would recommend you use the camera for now and see if you adjust to it over time.

[Dave Parker]

Well the Arca screen is a different size than any of the Toyo screens, so if your good at cutting small sections of glass, you may be able to fit a Toyo screen to an Arca camera, the measurements I have on file for the F is 100.33mm x 123.19mm and most of the Toyo's are larger. One thing I would suggest, make sure your screen in your Arca is clean, often times, environmental contaminants can darken screens and they are not visible to the naked eye, or even under a loupe. I would clean the glass itself with Dawn dishwashing liquid and hot water, using a scotch brite type pad, scrub is good on both the ground and the non-ground side. DO NOT do this to your fresnel or you will scratch it, if you need to clean your fresnel, use a very soft cloth, warm water and liquid soap. Then reinstall and test..make sure to observe orientation of your screen/fresnel combination. Now if you have grids, you will have to go a different route. Many of the various grids out there, can actually be removed by cleaning the screen.

Dave

[resummerfield]

I use several Arca's and have always found the gg to be equal or better than other makes. The Arca works well (for me) with all focal lengths. I have tried Beatties on other cameras and the Arca system is clearly superior. ........... I would recommend you use the camera for now and see if you adjust to it over time.Like Pete, I've used several newer Arcas, and I think the standard gg+fresnel Arca screens are superior to all others I've seen. I would NOT change the Arca screen.

[vonstauren]

Me too I'm fully satisfied with the Arca Swiss gg. The OP mentioned snapping in focus has to do more with the grain structure rather than with the gg luminosity. A finer grain gg is less prone to the sudden sharp focus snap, me thinks. It is something one can get used to after a time.

[marschp]

The OP mentioned snapping in focus has to do more with the grain structure rather than with the gg luminosity. A finer grain gg is less prone to the sudden sharp focus snap, me thinks. It is something one can get used to after a time.

Thanks everyone for responding so quickly. Since the original post I've spent some more time exploring focusing the Arca and I think my issue does arise from this idea of 'snapping' into focus. This was a very clear event on the Toyo screen, whereas its a bit more subtle on the Arca. I think for now I'm inclined to take the advice to persevere with the current screen.

Thanks

Paul

[Harley Goldman]

I owned an Arca for years and also had a Toho with a Maxwell screen. I found them to be very close in terms of brightness and ease of focus. Either it is a matter of getting used to the gg (which doesn't really make much sense to me as it is plenty bright) or you might have a defective product? Can you compare it to another Arca to see if they both look the same to you? Friend or local dealer?