Viewing card for 5x7 - help

[htswv]

Hi all...following the advice of Ansel Adams, Schaefer, etc I've decided to make myself a viewing card for my 5x7 to assist in composition of photographs. Schaefer recommended that I cut an opening as large as the film format I'm using....so, voila, I have a 5x7 cut out matte board.

Most of the examples that I see (Summitek 4x5 - see http://www.summitek.com/easel.html) use strings with knots that allow you to locate the frame at various distances from your eye that correspond to the field of view of your various lenses. The problem that I'm having is how to relate the distance of the card from my eye to the focal lengths of the lenses that I have since 5x7 is a different bird than 4x5. The lenses I have:

240mm Fujinon A
150mm Shcneider Super Symmar HM
450 Fujinon C

Does anybody know how I would go about creating a viewing card for 5x7 that's similar to the one shown above?

[Ole Tjugen]

It's just the same: A 240mm lens corresponds to holding a card with a 5x7" cutout 240mm from the eye. Mask the card down to 4x5", and it matches what you get on 4x5" film. Open up the hole to 8x10", and what you see is what you get on 8x10" film.

There's no "magic" involved - the focal length stays the same regardless of film format. The only thing that changes is the size of the film, or in the case of viewing cards: The size of the hole.

[Louie Powell]

Ini the for what it's worth department -

I made a couple of viewing cards for 4x5 - one resides in the car while the other is in my study. I have two lenses - a 210mm and a 90mm. The spacing dimensions are marked on the edge of the card for reference, but it turns out that 210mm is about the distance between by thumb and little finger with my hand stretched to its maximum, while 90mm is about the space across my fist.

[Ole Tjugen]

... it turns out that 210mm is about the distance between by thumb and little finger with my hand stretched to its maximum, while 90mm is about the space across my fist.

That's what I use across all formats: "Normal" is two spans with stretched arms, thumb to little finger. Wide angle (half normal) is twice that, and tele (twice normal) is one span. Then I fine tune based on the exact "section" I want, based on knuckles...

So all I need to know is what focal length is "normal" for the format. With more lenses comes more choise, but also more experience in translating spans to image angle!

[Bruce Barlow]

Set up the camera and focus it on something with references: i.e. - a tree on one edge and a wall on the other. Use one eye with the viewfinder and hold it in front of your face holding the string against you cheek with a Sharpie armed and ready.

Move the viewfinder closer and farther until it "sees" what the lens sees, with your references in the proper (if reversed and right-side-up) places. Make sure the string is snug to your cheek - no slacking. Voila! Mark string with armed sharpie (try to miss your face). Mount next lens. Repeat. I recently had to do this with my Zone VI viewing filter (not full size) with my 5x7 and 8x10 Sinar backs, and two new lenses. Took five minutes, with the most time spent changing lenses.

[Tim Hyde]

It's pretty simple: take a non-stretch cord of some sort and tie knots, beginning with your shortest lens, equal to the focal length for each lens you will use: If you have a 72mm, for example, tie your first knot 72mm out from the card. It helps to then blacken or otherwise color-code one or two of the middle knots so you don't have to count each time.

Ebony makes a titanium viewing frame for 4x5 (Midwest, etc), and I use 8-ply mat reinforced with duct tape for my 5x7 and 8x10. I warn you though, it's easy to become overly dependent on the viewing cards. I occasionally shoot with very competent photographers who never use them and always seem to know exactly what lens to select, while I seem to spend as much time with my cards as I do with the camera. Soemtimes I'll spend a couple of hours walking around a site framing various shots before I ever get the camera out of the rig.

[Sheldon N]

I used Bruce's method of setting the lens on the camera and findinging the fixed reference points in the scene, then positioning the viewing card to match. Tie a knot in the string, and you're good to go!

[Tim Hyde]

Just get a metric ruler and measure the knots. No need to fiddle with it in the field. You can do all your lenses in ten minutes with complete precicion.