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jim kerr

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Posts posted by jim kerr

    Help with neutral density filters please.

    in Accessories

    Posted

    Richard, I hope what I'm going to tell you isn't just some stuff you already know. Filter factors goes like this: For each stop that you need to increase exposure you will need .3 ND so for 15 stops, it's like this 15 X .3= 4.5 ND. I think B+W makes super dense filters, and B&H is advertising a ND filter with a density of 6.0, that works out to 20 stops, which figures out to an exposure time of ruffly 2 hours at f22; (maybe if you just left the lenscap on you could do a 12 hr. exposure). This 6.0 ND in 72mm thread is listed at $91.50 in the May 2005 issue of Popular Photography, page 146....go for it....Jim

    help a young photographer

    in Accessories

    Posted

    It's not what's between the subject and the photographer that is important, but what's on either side of the camera. About 25 years ago I bought a little Russian camera caller a Cosmic 35 for $15 new. Of the top 100 photos I've ever taken, 4 or 5 were with it....Jim

    EV of lightning for Pinhole Lightning Photography

    in Accessories

    Posted

    Anupam, my opinion as to using a pinhole for lightning photos is that lightning bolts are extremely bright something like the sun. I think what you will get usually would be just the lightning bolt itself. Ok, now you have done it, you have got me all worked up and interested, now I'm going to be waiting for some lightning. I have one of those body caps with a pinhole mounted in it's middle area(sold by Freestyle in California under the name of Finney Pinhole)....going to be an interesting little experiment....Jim

    Pentax 50mm F1.2

    in Pentax

    Posted

    Alkos, at any way of checking resolution, I think you have a very satisfactory lens. I have for many years wanted an f1.2 for astro-photography even though the outer 1/3 of the frame would be suffering severely from light fall-off....Jim

    "Auto" Vivitar Wide Angle 28 for Nikon is a bit loose.

    in Accessories

    Posted

    John, with the lens off the camera, I'd check all screws I could see to be sure they were tight, that's as far as I would think you should do yourself. Some lenses can turn into a basket case real easy when you start taking pieces apart. If there is a good camera shop nearby,with competent employees, that you frequent. If it is something simple that they can do,surely they would only charge you a nominal fee. If it needs to be sent in,they probably will know about the repair cost....Jim

    Pentax 50mm F1.2

    in Pentax

    Posted

    Alkos, That is one super f1.2 you tested there, even for center only. Did you get distinct separation of lines and spaces in both directions? I know it is possible that your lens gets l/mm readings that high, but in over 35 years, I haven't ever tested any lens(except super high quality macros in close focus mode) that ever got over 88 at any f-stop at a normal test distance(1:50). Please don't feel like I'm talking down to you,forgive me for sounding like I know it all. I'm just surprised at your high l/mm....Curious.....Jim

    When the aperture ring is set at other than the A position, shutter release is locked. - MZ30

    in Pentax

    Posted

    Yes, I was the same way. Finally got it through my head that the f/stop and shutter speed had to be set electronically on the body. Both are visible in the body's top screen and the viewfinder. Mine's the ZX-30, one thing I do particularly like is that when you have a varible maximum aperture zoom lens on, is that when you zoom, the camera changes the size of the lens opening to keep the same f/stop. Of course it can't do it if you are wide open at the short end though and then zoom out....Jim

    Telephoto lens

    in Accessories

    Posted

    George, if the cost of the lens isn't really a determining factor, I would think a Canon zoom would be first on the list, if the close focusing is the same. Over a year ago, I had to decide between the Tamron zoom and a Sigma 70-300 apo, both focused to 1:2. According to all the reseach I was able to do, the Sigma Apo was superior. I haven't been sorry I bought the Sigma.....Jim

    Finney pinholes

    in Accessories

    Posted

    I agree that putting a pinhole on a 35 slr does seem a little like cheating since it's so obvious and easy.But have been playing around with it off and on for probably since 1971 or '72....Jim

    Waist Level Finders

    in Accessories

    Posted

    Dave, I have one for my Pentax LX, comes in handy(like someone said, down on the floor), on a copy stand, microscope, telescope, or holding it up-side down above your head, to shoot over a crowd( better pre-focus though).....Jim
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