01 - STUDIO AND SHOOTING

This 101 series is aimed more towards the next steps of the process as the Studio setup and Photography will require a whole different and long series to be covered. That's why here I will only explain the basic principles of setting up the studio and doing the photos with some tips.

Studio setup - the goals of photographing the subject in a studio are achieving flat, diffuse textures and as perfect as possible aligning.

01. The first is achieved through smart placement of light boxes mainly focusing on front-lighting the subject. Two Light Boxes on both sides of the camera or a Ring Flash(?) and placement of the object in a Light Tent(?) are the most commonly used methods. Placing a Light Box pointed down towards the subject can also be very helpful.

02. Good aligning is achieved by placing our subject on a turntable which is then rotated and photographed usually at increments of 10 degrees (dividing the turntable with a marker helps for precision). The guys from Agisoft have released some nice markers which can be put on the turntable itself to help with aligning.

Photography tips - obviously a tripod is mandatory but here are a few more tips.

01. Camera choice - the more expensive the better! Well, it's not a joke. Still, equipment is quite expensive so the most important specs here are the size of the sensor (full-frame is preferable) and the resolution (the higher the better as PhotoScan software can then get more detail out of the photographs).

02. Lens choice - 50mm Prime Lens is the best one to be used - longer lenses produce too shallow focus zones and need to be placed too far away from the studio while wider lenses tend to distort the subject too much.

03. Aperture choice - depending on the size of the object Aperture can vary from 16 to 32. I really wouldn't advise going as high as 32 as even with Prime lenses a lot of diffraction can occur. Mind that it's not mandatory to have perfect focus front to back of the subject as other shots will fill in the gaps. It is better to have your focus point set at the front of the subject and of course turn off any kind of autofocus. An aperture of 16 will produce enough of a sharp zone for most objects while keeping diffraction to a minimum.

04. Shutter speed choice - even when shooting on a tripod the photos will benefit from having a fast Shutter speed. Any kind of micro-vibration is recorded by the camera and for example, moving just slightly on a wooden floor while taking a photo with a longer Sutter speed will affect its quality. To make sure you have the opportunity to shoot at faster speeds you need more powerful Light Boxes for your studio.

05. ISO choice - lowest possible that camera offers. Noise is a sworn enemy of good photogrammetry.

06. Distance from subject - the closer the better, obviously. After setting up the camera, make a test revolution of the turntable while looking through the viewfinder or on the screen to check if the subject won't be cropped at some point. This can happen easily with non-symmetrical objects if you haven't left enough bleed.

07. White Balance management - shooting in RAW is a must so white balance can be adjusted in a processing software. However, it's always easier to lock the WB. More importantly, before you start or after you finish a session, make sure to replace the subject with a Colour Checker Card and make an additional photo with it - this will help to get a colour accurate diffuse texture later on.

08. Number of rows around subject - this really varies for different subjects but generally 3 rows will do the trick - high, mid, and low-angle. This will usually be enough for getting 3/4 of the subject scanned. If your aim is to have a full subject scanned then rotating it 180 degrees (flip it) and doing another 3 rows is necessary.

Here are a couple of videos covering the basics of the workflow:

We can now move on to processing our photos and seeing the first results of our efforts in the studio.