I’ve just come back from an Alex Mustard workshop in Raja Ampat where I was predominately using a 140mm minidome on the D750. I was using it with the Sigma 15mm and sometimes with the 1.4x Kenko teleconvertor. I have to say that it has changed the way I think about FX underwater as I love the practicality of minidomes but did not want to compromise on quality. I am very pleased with the corner sharpness of the 140mm even up to F7.1 with the Sigma 15mm. Here are some images taken with the minidome.
1. D750, Sigma 15mm, F9, 1/60, ISO 500, 140mm minidome
2. D750, Sigma 15mm, F11, 1/60, ISO 500, 140mm minidome
3. On peut s’approcher très proche au subjet avec le minidome
D750, Sigma 15mm, F11, 1/125, ISO 320, 140mm minidome
With the 7D, I’d turn off the half-shutter press off so you are focusing on the rear button, find a suitable subject, no current or swell, and a place where you can put a sand spike to rest the housing on. Use the rear lever to focus to the magnification you want approx then release. Using the sand spike, gradually ease the housing forwards and backwards until you see the subject in focus and then pull the shutter. Take lots of shots as the DoF is very minimal especially as you increase to 1:1 on the lens. Think about the out of focus areas and how they will appear in the image. Breathe and work within depths that you are very comfortable with. Spend 30 minutes with a subject.
Just returned from a Photo workshop I was running in the Philippines. I didn’t take the 105mm macro off my D7100 for 9 days. Here are some results with the outrageously strong and sharp Nauticam SMC. Mostly uncropped.