I can't see when focusing!

[Removed Account]

Thanks to all who helped me with my film developing problem. I now have another aspect of use that I need to deal with. I can't seem to see when I am focusing. It may be that I am using a plastic drug store loupe so I will invest in a better one shortly. Part of it also has to do with my glasses fogging and problems holding the loupe while having to focus with both hands, but I can't do much about that right now. The biggest part is that I have problems telling how in or out of focus something is when it is close to being right, as well as seeing edges. Could this have to do with too much magnification on the 8x loupe? Also, there is a fresnel lens with 3x4 marking on it and I think the circles on the lens and 3x4 lines are making it even more difficult for me to see. If I remove the fresnel lens, will I have to recalibrate the focusing point on the camera back? How would I do this? Thanks again everyone!

- Justin

 

[jovo]

Yes, I think an 8x loupe is too strong. 4x is more typical. You should also consider using the dark cloth to let yourself stand far enough back from the GG that you can get the focus close or spot on without using the loupe at all. Use the loupe to check the usually darker edges and the center when stopped way down, but, if you're using movements correctly you shouldn't have to stop down as much in the first place. Good luck!

 

[Phillip P. Dimor]

Is it a problem w/ your eyesight? Or is the loupe to strong? The fresnel lines get in the way? I use an 8x loupe with a camera that has a fresnel. I use the loupe to verify the focus and adjust if need be. I compose using my plain eyesight under a darkcloth if one is handy. I do all of this with the lens wide open. As far as fogging goes, can't help much there as I don't have that problem. Although I have seen anti-fogging solutions that may work on ground glass. Not sure if you'd want to apply that to your glass.

 

[Charles Webb]

I believe that your problem is actually shared with a lot of us. It is extremely difficult to tell actual sharp from near sharp. I sometimes go back and forth in and out of focus trying to find the sweet spot. I most always use a Hasselblad chimney finder for a focusing loop and it works well, but it still does not always provide the answer to hitting the sharpest focus point every time. I still have to fiddle to get it right. I will frequently calculate DOF with a given lens and apperture. Then trust my findings to get the image as sharp as possible. I have the same problem with 35 mm SLR's, Pentax 6x7 and Rolleiflex. I have generally assumed that I was the only one in the world that lacked the ability to rapidly see sharp from near sharp.

Sorry that I don't have an answer for your question. but I did want to point out that others of us are also searching
for a working answer to the problem. I believe that a lot more folks than we know of are suffering from the problem
and perhaps like myself, they don't speak up about it.

Charlie................................

 

[Jon Shiu]

Hi, if you are nearsighted, try focusing without your glasses, just by eye, not with a loupe. Then you will get a feel for focusing.

Jon

 

[David H. Bebbington]

Thanks to all who helped me with my film developing problem. I now have another aspect of use that I need to deal with. I can't seem to see when I am focusing. It may be that I am using a plastic drug store loupe so I will invest in a better one shortly. Part of it also has to do with my glasses fogging and problems holding the loupe while having to focus with both hands, but I can't do much about that right now. The biggest part is that I have problems telling how in or out of focus something is when it is close to being right, as well as seeing edges. Could this have to do with too much magnification on the 8x loupe? Also, there is a fresnel lens with 3x4 marking on it and I think the circles on the lens and 3x4 lines are making it even more difficult for me to see. If I remove the fresnel lens, will I have to recalibrate the focusing point on the camera back? How would I do this? Thanks again everyone!

- Justin

Don't know what camera you have - if your camera will accept a binocular focusing hood, this is a great solution - you can see with your regular glasses, plenty of ventilation so no fogging, works fine even in bright light, will not blow around like a focusing cloth.

As regards in/out of focus, it is strictly speaking impossible to see how sharp something is on a GG because of the grain of the glass. I am a very experienced LF photographer, I never use a loupe because I find all I can see is grain. All you can see on a GG is whether something is in focus of not, i.e. you can move the focus back and forth until the image looks least blurred. I would think in any case a cheap loupe is no use, it will have a curved field and probably color fringing. I would not attempt by viewing the screen to determine the limits of lens coverage, instead look up the lens data sheet and either carry this with you or memorize how many mm rise you can safely use. Trying to judge sharpness at the edge of a GG with a wide-angle lens at f32 is not for those who value their sanity.

A fresnel screen should always be a help, unless it is very scratched or dirty. If in doubt, experiment with and without. Some cameras like Sinar allow you simply to unclip the fresnel, if this is installed on top of the screen, there will be no focus shift if you take it out. If the fresnel is under the screen, you will have to put in a spacer (e.g. plain glass of same thickness) to compensate. for the absence of the fresnel.

Regards,

David

 

[David A. Goldfarb]

If the texture of the glass and the fresnel is distracting, then your loupe is too strong. Try a 4x loupe.

What camera do you have that requires focusing with two hands? There might be knobs on both sides of the camera, but normally that is just for convenience. You should be able to focus with one hand and hold the loupe with the other hand. The loupe should have a lanyard, so that you can hang it around your neck for operations that require two hands, and then you'll have it handy when you need to make the fine adjustment. Once you can work more comfortably, maybe that will help with the glasses fogging problem.

Also, be sure that your darkcloth is dark and you close off as much extraneous light as possible, and that you let your eyes adjust to the darkness. This will take care of many focusing problems.

 

[photomc]

I think you nailed it Charlie...