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Thread: focusing aid

  1. #1

    focusing aid

    I am just getting started in LF. I have been reading past posts on focusing with a loupe. There seems to be agreement on about 4X or 5x and the fact that the qu ality of the loupe is not really that imprortant. I was wondering if anyone has ever tried an Optivisor. This is about 4x. I have been using one for model work. It would seem to me there would be an advantage to having both hands free to wo rk the camera. Am I overlooking some disadvantage to this system? Thanks. JimJ

  2. #2

    focusing aid

    Jim,

    I bought a jeweler's loupe--just a simple eyeglass frame with a set of fold-down magnifying lenses that allow you to focus on and see tiny objects about six inches away from the lenses--for that very same purpose. It works OK for quick focussing on the groundglass when I don't want to remove both hands from the controls (when doing tilts, rise and fall movements and the like), but it will not replace a good quality loupe for really accurate focussing.

    It works well for setting up the preliminary focus of your shot, but it is not sharp enough to do really fine-focussing. These things are relatively cheap, I paid about $20. for mine, so it's not such a big deal if you don't like it. There are several other more expensive versions of the jeweler's loupe that might provide a sharper, clearer image.

    At one time I also used one of those "sucking loupes", sold by Calumet. You attached it directly to the groundglass with a suction cup surrounding the glass element. That also worked OK, and allowed me to do loupe-focussing with no hands. It was limiting, since you could not easily move the thing around the groundglass. And a couple of times I nearly broke the groundglass trying to remove it. I lost it and never replaced it. I'll mercifully avoid the obvious (and easy) characterization of the usefulness of this device.

    I use a couple of different loupes for fine focussing, a 4x and a 7x, and sometimes I wish there were an easy way of holding these directly onto the groundglass while performing some of the more involved movements. It's just another one of those things you have to put up with if you're doing LF work.

    Good luck, Sergio.

  3. #3

    Join Date
    Feb 2001
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    Los Angeles
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    focusing aid

    Jim: I used to use a loupe, 4 power, and it worked fine. Then I started using the cheap dimestore reading glasses. Depending on your eyesight, something in the 1.5 to 2.5 range will let you get a great view of the ground glass. (If you use a fresnel lens, it seems to me that the view screen has a focal length of its own, which means your head has to be further away, so the higher powers can be too much.) The reading glasses are light, cheap ($9 to $2) and folded don't take up much space. If you hang them around your neck on a lanyard, you can just drop them when you're done and they don't go anywhere.

  4. #4

    focusing aid

    I've been toying with the idea of getting a small flexible neck (6in- 8in) with a clamp, i.e., a small clamping gooseneck, and attaching my loupe to it also using a clamp (so it is removable, too). I could attach this to the top of the back and position it over the spot I want to focus on flush agains the GG. It would be compact enough to fit under the cloth and be hands-free. For focusing on a far point and tilting for a near point, in landscape work, I could even have a double-necked clamp with two loupes......wait a minute. I'm getting carried away. How practical do you think this might be for a single loupe?

  5. #5

    focusing aid

    Jim: One requirement of the loupe is that be long enough so that you do not have to rub your nose on the GG. Another is that it offer sufficient magnification and ample enough coverage. Therein the contradiction. 10X loupes used to be very short. However, some modern loupes meet these requirements even up to 10X magnification as for example the Silvestry 10X. This is a very sharp loupe with a wider field of view than most regular 10X loupes and just long enough to keep your nose where it belongs. Below 7X I personally feel that the magnification is insufficient. Above 10X it is too high and the grain of the GG becomes overwhelming. The good loupes are expensive but I think worth it. Drugstore glasses are ok but do not offer sufficient magnification. If you wear prescription glasses you can have them formulated so that you can see the whole 4X5 screen at about 6" at good magnification, but in no way substituting the loupe.

  6. #6

    Join Date
    Jun 1999
    Posts
    78

    focusing aid

    Try the 7X Calumet. Seems perfect in every way.

  7. #7
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    focusing aid

    For a long time, I used makeshift devices as focusing aids. But, this summer, I had a chance to purchase a 4x, Calumet aspheric loop designed for focusing on ground glass.

    What a dream. Using this device, the image on the ground glass just seems to snap into focus. It's relatively large, so you have a good viewing area of the image. It's also adjustable, so that you can make sure that you have the correct plane of focus. I would say, go with devices that are designed for the purpose. It makes life so much easier.

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