Seeking LF advice

Discussion in 'Large Format' started by avid, Oct 25, 2004.

  1. I am getting into LF landscape photography and started with a used
    Toyo 45G and my initial experience is becoming rather frustrating. I
    can't seem to see the projected image on the GG to get the focus
    right. I changed the GG to a Canham grid type hoping the image would
    be brighter but to no avail. And this is using a dark cloth. The
    first transparencies have out of focus areas because I couldn't see
    the dim image to judge focus. The lenses I used vary from f/6.8 to
    f/8.0. I am sure people focus fine with such slow lenses too or
    should I get faster lenses to end the problem? In Jack Dykinga's LF
    photography book, there is a shot of his camera's GG with an image of
    the scene without a dark cloth. Why can't I have such a bright image?
    Does it help to use a reflex magnifying viewer or other viewing
    hoods? Can you still focus sharp with one of these on? One
    photographer told me he prefers dark cloths but not why. I wish I
    could have bright images in LF like I do on my MF cameras. Does
    anyone new into LF here share my feeling about dim GGs? I am sure I
    am going to plague this forum with a ton of more questions as I try
    to familiarize myself with this uncharted LF territory. Thanks for
    any advice.
     
  2. instead of a dark cloth i use a coat im wearing.. you need a fresnel on your camera back.. its the frosty part of glass, .. im an amature so im strugeling here, but otheres will correct and hopefully give more info.. during the day a 8.0 can be ok and the areas can be checked with a 10x loop.. i use a slide magnifier, that is plastic and sanded down to correct focus depth at the surface it sets on... its cheap and its backward and its black on theout side so incomeing light doesnt cheapen the image..hard to exlain.. sometimes if you focus the corners your ok.. as trees, and buildings and uneven landscape enter in your focus can get out in the middle also.. the best way to get around this ive found is to use a hyperfocal distance chart to determine focal distance of close and far,. use the correct f (add a fudge factor) to cover your butt for more focus depth.. in time youl find sweet spots that your lens, film, and subject likes and all is in focuse.. for example for my 135 lens at f 11 and i focus at 100 feet on my crown graphic its in focus from 35feet to infinity, at f22 with focus at 30 feet its in focus from 14 feet - infinity.. i also have good spots noted for f 16 and f 8.. the crown has a distance measure on the bed.. when useing view camera special features(movements) youl need to check for vignetting by looking in the corneres and you should see the entire lens opening.if it is not round then your being blocked by the lense rim , camera bed , filter, hood, etc.. then use the loop in the corners for focus, and if really picky check every square inch of the 4x 5 format... alot of work but well worth it when it comes out correctly..remember an item not in focus at f8 may be in focus at f32. the lens also will have a clarity sweet spot usually in the center of the f settings .. make sure to use film that its resiprosity will not change color or otherwise defect when using long exposures.. velvea is really great for scenics and long exposures if you can get the buffalow to hold still..i found out the hard way they can moove a long way in one minute.. if you have alot of time for the shot you can get a 405 polaroid back and it will give a polaroid in the center of the shot, giving exposure and some focus detail but polaroid is not really great for super clarity, but good for exposures, catching the pole growing out of grandmas head, grandpas zipper not zipped a beer can in the foreground etc.. . good luck dave..
     
  3. d_g

    d_g

    it depends on a lot of things !!! subject, available light, max. F stop of the lens, fresnel or
    not, bright focusing screen or not, and actual focal length !
    A 240 f9 seems brighter than a 75 f5,6, that's life.
    With wide angle it's sometimes difficult to use a reflex viewer, because you need to move
    your eyes to see some part of the image (direction of light !).
    I would try first to use a fresnel, a good dark cloth, if it's not enought then f5,6 or 4,5 lens
    have to be in you wish list for santa !
    Reflex viewer is very good sometimes, but it does not brighten the image at all !

    Using a 180/5,6 in daylight it's very easy ... using a 65/8 in rising sun it's an other story !
     
  4. How close is your eye to the gg when you focus? Are you using a loupe?

    Few people can focus accurately enough at normal close-up viewing distance of about 10-12 inches. A loupe lets you get close enough to see small detail. Most people find a loupe of about 4 X about right. Higher power loupes may lead you to focus on the gg surface rather than on the image.

    I've used my Toho FC-45X with the gg that came with the camera, which was a fairly basic kind of screen. I used it with a f/6.8 90 mm len, a f/5.6 150 mm lens, and f/8.9 300 mm lens. I got myself some special +5 diopter reading glasses which allow me to get about 7 inches from the gg, and I also use a Toyo 3.6 X loupe. I did have some problems with the f/6.8 90 mm lens in dim light. Usually I was okay in bright light, but I sometimes would have problems at the edges of the image. The other lenses didn't pose a problem. I eventually got a Maxwell screen, which is much brighter than any other screen I've seen, and now I never have any problems.

    You should look at the advice about focusing at
    www.largeformatphotography.info
    The focus spread method described there often solves focusing problems.
     
  5. Avi,
    Since you're just starting out, what lenses are you using? Do you have long enough bellows to focus them? It sounds like this may be your problem. Also, (and this is really basic, but surprisingly is often overlooked)are you sure you're trying to focus with your lenses wide open and no film holder in place? Are your camera's movements in a neutral or detent position or are you trying to focus after adding swings and tilts? These are problems that are often encountered when making the jump to LF. Good Luck!
     
  6. get a fresnel screen to go over your groundglass.
     
  7. Your Toyo G camera should already have a build in fresnel lens to make your ground glass more even and brighter, but if this is still a problem, you should consider the Beattie Intenscreen system. Beattie Intenscreen replaces your existing ground and fresnel lens, this should give you the brightest viewing possible. A good focusing loupe with dioptric adjustments will help too in obtaining the sharppest image. Lastly, a good focusing cloth that is truly light tight is a must for outdoor photography. Your problem is that you have not talked to anyone that could teach you shortcuts to make your experience with LF better. You need to talk to an experienced LF dealer/sales person to set you up right.
     
  8. Are you referring to the photo on page 60 of Jack Dykinga's book "Large Format Nature Photography"? If so, the brightness difference between the ground glass image and the scence may be greater than you think. The scence is in full, direct sunlight, while it appears that the camera is in the shade -- at least the back of the camera is in the shade. This difference in illumination between the scence and the camera helps in making the ground glass image more visible.

    The image is fairly dim and would definitely be underexposed if it were a regular photograph. In contrast, the scence seen beyond the camera is very well exposed, bordering on overexposed. The entire reproduction process, from reality to printed page, reduces the brightness range. So there really is a large brightness difference
    in this photo between the ground glass and the scence.

    LF photography takes some practice. As already suggested, a truly opaque dark cloth will help. Also hold the dark cloth so as to minimizes light leaks that shine onto the ground glass. With the extraneous light blocked, your eyes will adjust so that you can compose and focus. You need a loupe to focus with sufficient accuracy. While I don't like Fresnel lenses (I find the lines distracting), one will brighten the image.
     

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