Photographing paintings - squaring camera to painting

[rechmbrs]

I found http://www.thephotoforum.com/forum/beyond-basics/160736-photographing-oil-paintings.html sometime ago and have used the advice from Dwig with success. I have a second problem that I must do some shooting with the paintings in-situ. Some are hung and others on easels.
Problem I see is to make film plane parallel to painting which I can not physically touch in anyway. Anyone know of a laser measuring setup? Some other way?

Really appreciate the insight I've gained from this forum.:blushing::blushing:

RON C

 

[Garbz]

... Don't you have a viewfinder to use to line up the image? If it's slightly off then you can always tweak it slightly in post without any noticeable difference.

 

[Mike_E]

Hi Ron, if you are serious about this then you either need a tilt shift lens or a large format camera. Manipulating the lens will bring in the image with a cancelling distortion.

If you don't already know how go to a library and spend some time with Ansel Adams' Camera And Lens and you will be well rewarded.

P.S. there are 5 books in all, they would a great addition to your library or the beginnings of one. :thumbup:

 

[craig]

A torpedo level is your best friend in situations like yours. Level the art. Then place the center of your lens in the center of the painting. Level your camera horizontally and vertically. Miner adjustments will need to be made vertically because paintings do not sit perfectly flat on the wall. Horizontal adjustments are less critical.

I have shot in many galleries. Generally they are willing to take them off the easel and on to the wall. The easel can take some time to straighten.

Love & Bass

 

[Mike_E]

OR just tell them you know Craig and move the objects to suit you.

:lmao::lmao::lmao::lmao:

 

[Dwig]

A camera with a tilt/shift lens would, of course, be of absolutely no help. You would still have the issue of determining when the camera back was properly aligned. A shifting lens would only be of use in situations where it is impossible to get the camera centered on the painting.

Determining when the film/sensor plane and the painting are parallel is difficult when you can't touch the painting and the painting is not parallel to some touchable surface. Even determining the center axis is difficult.

One approach is to eyeball it using a VF with grid lines for reference. This can work reasonably well but doesn't have very high precision in some cases. Using a lupe on the viewfinder (ground glass of a view camera or LCD panel of a digital with a Live View display) can help.

If you can "almost touch" the artwork you may find the "lens cap and a string" approach helpful for finding the center axis. This involves attaching a string to the center of a lens cap, placing the lens cap on the lens and using the string to determine if the four corners of the art (or its frame if its uniform enough) are equidistant from the lens. You might find using a straw or similar tube, threaded on the string, as a handle at the picture end so that you can safely hold it very near the art without risking a touch.

 

[Mike_E]

I am probably off here but getting the camera parallel to the wall upon which the painting is hung is just a matter of using a tape measure, some painters tape for the floor (parallel to the wall to use as a reference to sight in the camera back) and a level. After that the tape measure is used to determine the angle the painting is hanging, which could then be offset by the t/s lens. Harder to describe than to do.

If you only have a few to do though it would be better to get the camera set up as above then adjust the camera via the tripod head for the angle of the painting to get the camera parallel to the painting and then just crop for what you need in post. (unless you just want to spend 2 grand on a lens. )

 

[craig]

OR just tell them you know Craig and move the objects to suit you.

:lmao::lmao::lmao::lmao:

Better yet tell them you were my assistant for 2 years. That way could charge them double.

Love & Bass

 

[Dwig]

I...after that the tape measure is used to determine the angle the painting is hanging, which could then be offset by the t/s lens. ...

If you are talking about determining the lens tilt mathematically then you need more info and a very finely calibrated tilt on the lens. You also need to know several distances (sensor/film plane to artwork plane, the angle that distance line intersects one of the planes, distance from the film plane to the tilt axis of the lens) and do some complex math. If you are talking about determining the tilt visually then knowing the angle of the painting relative to the image plane is of no value.

If you get the camera on the axis of the painting exactly centered (as my string method will do) then visually centering the painting will get the camera back very, very close to parallel. This is easier and of higher precision than visually judging whether an edge of the painting is parallel to a grid line in the VF, at least with most VFs where you can't move a grid line to be close to an edge in the subject.

 

[rechmbrs]

Thanks a lot guys.

This just made my holiday as I got another lump of coal (wrapped this time) for Christmas.

All insights were helpful and Dwig you hit it on the head. I will test the string method at home using just tripod and an eye (from hook and eye) attached to the tripod. Should be able to thread the string through the eye easily. Once I'm happy with that, I'm going to try a stiff pullout measure and attach to tripod and see how stiff it is and whether it will do it without toughing. I'm also going see if I can find an accurate laser range finder and attach it to the tripod and test also. No touch and I'll bet pretty accurate.

I've lurked around here for a long time but don't seem to offer much but I sure gather a bunch.

Thanks again and Happy Holidays.

RON C