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Thread: Loupe focussing issue

  1. #11

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    Re: Loupe focussing issue

    Quote Originally Posted by Doremus Scudder View Post

    FWIW, I've been drooling over this Silvestri loupe for some time now... http://www.silvestricamera.com/ita/c...ng.asp?ID=5050

    Best,

    Doremus
    Oh my goodness, now that I have seen this, the appeal is heightened by the possibility of actually seeing the corners of my 65mm lens on my 4x5 cameras to a degree that will allow focusing check, among other things. Seeing something so obviously well thought out and with some original thinking in the design, makes one wonder just what will some people around the world think of next that we don't know we will lust after.

    Thanks for that link.

    Mick.

  2. #12
    Jac@stafford.net's Avatar
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    Re: Loupe focussing issue

    Quote Originally Posted by Mick Fagan View Post
    Oh my goodness, now that I have seen this, the appeal is heightened by the possibility of actually seeing the corners of my 65mm lens on my 4x5 cameras to a degree that will allow focusing check, among other things. Seeing something so obviously well thought out and with some original thinking in the design, makes one wonder just what will some people around the world think of next that we don't know we will lust after.
    Please excuse my skepticism: it was born into me. The angle view of the Silvestri loupe is a gimmick. If you understand your lens, and you should, then focusing within the 50% central area should suffice. You know the rest of the focus area.

  3. #13

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    Re: Loupe focussing issue

    Quote Originally Posted by Jac@stafford.net View Post
    Please excuse my skepticism: it was born into me. The angle view of the Silvestri loupe is a gimmick. If you understand your lens, and you should, then focusing within the 50% central area should suffice. You know the rest of the focus area.
    Your scepticism is noted, and yes, you are correct

    However with a centre filter on and photographing an engine bay in an automobile, there is a very fine line between acceptable focus, which happens around 2 stops down, and very good focus which more or less, really gets underway around 2 stops down. But, as the camera is sometimes not at 90 to the engine, due mainly to a non removable bonnet getting in the way; compromise is the order of the day.

    I currently use a linen counter loupe, as I can hold it loosely above the GG at any angle to ascertain if in fact, I have acceptable, close to acceptable, or, borderline acceptable on the corner that must be in very good focus.

    As strange as it may sound, and shortly after purchasing my 65mm lens for 4x5" I have been photographing some of the engine bays of a private collection of interesting automobiles. Something I never in my wildest dreams I thought I would be doing. I am using a column stand with an extending arm that is capable of holding 10kg of camera 1.4m from the column. This was built expressly for this job by the in-house mechanic after I initially declined the invitation to photograph the engine bays, as I didn't have a suitable camera mount. Using sand bags, the 10Kg limit can easily be exceeded; bit of a once in a life time job.

    I picked this exercise up when the owner of the collection saw me photographing our car with my camera about 45cm off the ground, and about 40cm away from one of the front corners of the car. He looked at what I was getting on the GG; the rest is history, as they say.

    That said, I do not ever see me picking up one of those loupes. I would love to have one, it isn't going to happen, but one can lust after one, can't one?

    Mick.

  4. #14

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    Re: Loupe focussing issue

    Quote Originally Posted by Jac@stafford.net View Post
    Please excuse my skepticism: it was born into me. The angle view of the Silvestri loupe is a gimmick. If you understand your lens, and you should, then focusing within the 50% central area should suffice. You know the rest of the focus area.
    Jac,

    I don't know about the Silvestri loupe, but changing the angle of view of the loupe for viewing the corners of the ground glass, especially with shorter lenses and when using extreme movements, is a real help. As mentioned, I use smaller 8x loupes and use them inverted, that is, with the skirt toward my eye. This allows me to view at any angle to the gg. I find I have to hold the loupe significantly off of perpendicular for many situations in order to find the bright spot for best focusing. If the Silvestri loupe can do this with the base resting on the gg, then it should be a great tool. For many of my shots, there are near objects at the edge of the image that I really need to focus on; using just the center 50% is a no-go.

    Best,

    Doremus

  5. #15

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    Re: Loupe focussing issue

    I use the Silvestri loupe - it works as advertised. Another reason I find it useful is that I often have things in the edges and corner that are visually important but require DOF to keep in focus and I prefer viewing under a loupe over using a formula (or in addition to...). In general, I have come to appreciate the use of triangulation - anything important is worth figuring out in 2-3 different ways to check if all methods point in more or less the same direction. Viewing the corners with the lens stopped down can be hard and the Silvestri does handle that well. It is also small and light and well made. Cheers, DJ

  6. #16

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    Re: Loupe focussing issue

    I have had a disastrous few months taking shots, I have a Shen Hao 4x5 and a Horseman FA 4x5, I have been using the Shen Hao with a Maxwell screen, and my pics have all been slightly out of focus. I retired the Shen Hao thinking it had a soft ground glass IE slightly out from the film plane, but have been that disappointed with the images I haven't shot any images since. Recently I bought a new to me Nikkor sw 90mm f8, took a sample shot to ensure it was no dud with my trusted Horseman FA 4x5, once again a slightly out of focus shot. I then remembered my good loupe, a linen checker type, had been bent and I had turned to another loupe. On a whim I checked the loupe on a newspaper with fine lettering, sure enough there was my problem. I adjusted it to suit my eyesight and glued it in place so it could no longer lose focus. The new lens now performs admirably and I can get back to shooting images.

  7. #17

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    Re: Loupe focussing issue

    Quote Originally Posted by andrewch59 View Post
    I have had a disastrous few months taking shots, I have a Shen Hao 4x5 and a Horseman FA 4x5, I have been using the Shen Hao with a Maxwell screen, and my pics have all been slightly out of focus. I retired the Shen Hao thinking it had a soft ground glass IE slightly out from the film plane, but have been that disappointed with the images I haven't shot any images since. Recently I bought a new to me Nikkor sw 90mm f8, took a sample shot to ensure it was no dud with my trusted Horseman FA 4x5, once again a slightly out of focus shot. I then remembered my good loupe, a linen checker type, had been bent and I had turned to another loupe. On a whim I checked the loupe on a newspaper with fine lettering, sure enough there was my problem. I adjusted it to suit my eyesight and glued it in place so it could no longer lose focus. The new lens now performs admirably and I can get back to shooting images.
    Except you may not have solved your problem. If your loupe has adjustable focus then you must set it for the grain of the gg. Not for the top surface. Which it would be if you adjusted it on a sheet of paper.
    To adjust it for the grain side of your gg first remove the camera lens. Then point the camera at a light source and adjust the loupe till you see the gg grain sharply. Now replace the lens and shoot.
    The way you did it means that you are out of focus by the thickness of your gg screen and anything laying on top of it!

  8. #18

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    Re: Loupe focussing issue

    I read this thread as it resurfaced because I'm having problems focusing and now I understand why. I used a loupe with a skirt but it is made for printed matter and so it doesn't focus on the right side of the ground glass.

    This is a very useful forum. Thanks.
    Expert in non-working solutions.

  9. #19

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    Re: Loupe focussing issue

    Quote Originally Posted by Bob Salomon View Post
    Except you may not have solved your problem. If your loupe has adjustable focus then you must set it for the grain of the gg. Not for the top surface. Which it would be if you adjusted it on a sheet of paper.
    To adjust it for the grain side of your gg first remove the camera lens. Then point the camera at a light source and adjust the loupe till you see the gg grain sharply. Now replace the lens and shoot.
    The way you did it means that you are out of focus by the thickness of your gg screen and anything laying on top of it!
    That makes sense, thanks Bob

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