What NOT to do in large format ?

by Q.-Tuan Luong for the Large Format Page

There are more ways to ruin a photograph than you would think. All these potentially fatal mistakes are specific to large format, in the sense that most of them are impossible, or quite rare with 35mm and MF cameras. Here are some of them, and how to avoid making the mistake. Additional suggestions welcome.

To avoid fatal confusions

Be sure to operate in a systematic way, to always do the actions in the same sequence, and to double check everything. After I am done focussing and composing, the first thing I do is close then lens. Then I meter, and set the f-stop and shutter speed. Then I insert an holder, making sure it is white. By prefiring the shutter before pulling out the dark slide, I make sure that the lens is closed and that an (approximatively) adequate shutter speed was dialed. By checking that I put the black side of the dark slide back, before removing the holder, I make sure that the exposure was done.

To avoid vignetting

Always check through the cut corners of the ground glass in doubt. It is useful to know the situations where problem can occur. For instance with my camera, I have to be careful if I don't use bag bellows and do tilts or falls in verticals.

To avoid lack of sharpness from focussing

Use a lupe to focus, and check very carefully each part of the ground-glass. In particular, be aware when using tilt that the depth of field around the focus plane is significantly reduced as compared to the case when no movements are used, so don't forget to check the top of the trees or hills. If there are areas in the image which still appear unsharp after applying movements, stop down until they appear sharp, and then add one f-stop. This might be difficult to judge with a dim image. Better to loose some optical performance by overstopping than to have an area which is lacking critical sharpness. Wide-angle lenses usually have to be stopped down to f22 for optimum performance anyway, whereas other lenses have to be stopped down a couple of f-stops. It is not a good idea to use a lens near full aperture because of the possible alignments problems.

To avoid unlock controls

Lock all the controls as you unfold the camera. Unlock only those that you use. Double check that camera controls and tripod controls are locked before inserting the film holder (which would otherwise cause the back standard to move and force you to refocus).

To avoid camera shake

Use an unbrella to shield the camera from the wind. For long lenses, techniques comparable to long-tele tricks like double tripods or extension arms to support the standard help. More details.

To avoid subject shake

Be patient enough to wait for lulls. Using the fastest speed (compatible with the desired depth of field) helps too.

To avoid underexposure

If you are going to do a long exposure (several seconds), a close-up, or use filters, think about the compensation to apply. Reciprocity compensation tables are available for most popular films. There are several methods to accont for bellows factor.

To avoid last second problems

Be sure to look at your subject until the moment you make the exposure !

To avoid improper loading

You must feel the film with your fingers to make sure it is well sitted in the rails. The things I do is feel the extremities of the rails, which ensures that the film is beneath. I also lift the film from below and makes sure it is catched by the rails. See detailled description of loading

To avoid loading backwards

Make sure you feel each notch at the right place. If you are holding the long side of the holder perpendicular to you that's the right corder on the upper side of the film. If you are holding the holder another way, be careful.

Once you have shot your film backwards, it will appear underexposed by 2 or 4 stops, and if you are shooting color it will have a predominant red color cast because it has been filtered by the base. Color film is ruined. B&W can be salvaged: " Develop in a very active developer such as Xtol or Microphen -- use a concentrated dilution, not a weak one, particularly with Xtol -- and add 30-40% to the standard development time for your film. It'll be okay. Thor Lancelot Simon"

To avoid dust

Some say that the only solution is to use preloaded film (in 4x5), and recommend to shoot a backup when there are large tonal areas which would be ruined by dusk. A picture can be also saved by spotting. I try to avoid using the changing dome whenever possible, by using bathrooms or closets at night, sealing the openings with the dark cloth. My procedure is the following. I clean each holder with a paintbrush and sometimes canned air. I insert all the darkslides with the white sides facing out, leaving only about one inch open, and I stack them on top of each other. This minimizes the chance of the dusk getting on the holders or inside. I open the film box, but keep the film between the two cardboard sheets, and put it on my knees. I extract each sheet of film only to load it, which minimizes the time it can collect dust. When the loading is done, I put the holders directly into plastic ziplocks.

To avoid forgetting equipment

Put everything in the same place, and use a check list.

To avoid opening holders

Make sure to reposition the tabs which prevent accidental opening. They tend to come loose very easily. Be careful whenever you grab your holders.

To avoid cross-processing

Write on a separate sheet of papers the nature of each sheet exposed (and, if you are really serious, exposure information, etc...)

To avoid other dumb mistakes...

Triple check and good luck :-)

The mysterious double image

After long exposures, if you are not lucky, you might observe a double image on all or part of the film. There seem to be four distinct causes: (based on comments by Paul Butzi and Jonh Sparks.)

Light leaks

Test all the suspects elements (more details). It can be holders, camera, or the combination of both. Some sort of flare, due to the large image circle light bouncing off belows, can also look like a leak. Readyload holders require particular precautions. Covering the camera with the dark cloth while the film is in it might help.

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