4th Aug 2015, 04:29 PM
All that jazz: sensors, focal length, lens size, control placement.
I know what I want but I'm having trouble finding it:
A small-sensor (1/2.3) camera, with a close-focusing (1") wide angle (24mm effective focal length), with adjustable ISO and aperture, with a tiny lens off in a bottom corner.
Here's how I arrived at these specs:
1. Small sensor will have the greatest depth of field at a given aperture and field-of-view (and I don't anticipate viewing larger than 8x10 images).
2. Close focusing is necessary to place the camera close to the model train. An observer standing at the head end of a prototype passenger train will see a locomotive dominating the scene, with the cars tapering toward a perspective vanishing point as one looks to the rear. To achieve a similar view of a model, the camera has to be placed much closer to the train than the size of the train itself, and achieve close focus at that distance. (Helicon focus stacking can incorporate distant objects). And if you get this close to the model, you'll need a wide angle view to see the whole thing.
3. For realism, the lens location should be at about the height of a scale person, and a corner lens is nice because you can find some way of intruding it into interesting places, like a station platform, or at the bend of a curve (where close placement will give a strongly-tapered view of the rails as they recede from the camera). (A stick-shaped camera would be ideal).
I do NOT want any camera with a large lens, nor with a large sensor, not because of the extra expense, but because they're technically inferior for shooting small models realistically. The geometry of a smaller sensor and lens is more conducive to getting realistic perspective, and gives better field depth as well.
I DO want to be able to shoot at low ISO, to keep digital image noise down. And closing down to a small aperture will give best depth-of-field. These conditions will probably require either bright lighting, and/or very long shutter speeds.
I've taken some experimental photos, using a Pentax K10d/50mm macro SLR, a Panasonic FX-01 sub-compact, and a Rugby phone camera. The SLR is hopeless, providing an unnatural perspective and having no depth of field, not to mention being impossible to place in a realistic position. The Panasonic at the wide setting almost works with a 30 sec shutter opening. But lens position and size are cumbersome, and it's still too big. The Rugby lens is tiny and in a corner at the outer end of the flap, which gives great perspective, but no aperture or ISO control, so no field depth control, unfortunately.
Of other cameras I've not tried, the Sony TX series looks possible, but controls are in the wrong places.
Has someone seen a controllable micro-camera module with the above specs that does stills instead of video?
4th Aug 2015, 08:37 PM