I would ask the student always to use the longest focus lens possible, consistent with the effect desired.
The use of extreme wide-angle lenses has had a disastrous effect upon the public taste in respect to architectural photography due principally to the abortions one sees exposed for sale in the shop windows of our cathedral cities.
It should be seldom necessary for the amateur to use very wide-angle lenses. Of course, when it is a question of getting a detailed photograph in a confined situation a wide-angle lens is of great service. But it is when you see the whole length of a cathedral photographed on a whole plate with a five inch lens that the fault is so noticeable.
In photographing exteriors great care should be taken in the placing of the camera in a suitable spot. Try and so arrange it that the short side of the building does not run off too violently, indeed, it is often much better to leave out a portion of the subject rather than to cram the whole subject upon the plate.
General views are much better if photographed when there is a little sunlight. This gives to the subject a sharp, clean-cut appearance.
Details on the other hand are better if photographed in a subdued light and slightly over-exposed.
In focussing very high subjects some difficulty will be found in getting bottom and top in focus at the same time, especially if the lens be strained by either altering the back or front of the camera.
The best place to focus is a little way above the centre of the screen, so that when stopped down the bottom of the building is quite sharp. A slight softness towards the top of the subject is scarcely noticeable in the final print.
The exposure of exteriors varies between three seconds at f/64 to ten minutes, and no correct guide can possibly be given. To the beginner a Watkins' exposure meter will here be of some service.
If people are continually passing and repassing stop the lens down to f/64 and give as long an exposure as is possible; this will as a rule completely obliterate them. I have found that an exposure of from ten to twenty seconds entirely destroys all trace of moving objects.