Just photograph a grey card (or white wall etc. ) at
f/1.2 at approx. the green button exposure, but set it
in manual to nearest full speed say 1/25th sec.

Take extra shots at same speed stopping the lens down by
half a stop between each. Do it to about f/2.8

View the thumbnails in a viewer such as ACDSee Press PrntSC
Fire up an editor PASTE Clipboard and read off RGB values
from each shot, should be around 117R 117G 117B

Is there a difference between f/1.2 and the frames following?
Is f/1.2 and f/1.7 the same RGB value? If it is the camera
is seeing the lens as f/1.7 wide open.

Ha! Ha! It's camouflaged so you can't see it!

The Sample Shots on page 2 are the sharpest digital shots I've
ever seen. Click on the 1st shot to see 100% crop, you can see
all the fine detail around the child's eye even the pores of
the skin with almost no noise

I think you would get a better idea searching Google, that way you cover all the forums not just one.

The SMC A 35-70mm f/4 is a superb small lens with a constant aperture.
Make sure that it's clear and not suffering from any cement/element
separation. Sharper than the F 35-70mm

The SMC A 70-210mm f/4 is also excellent.

I'd forgotten about B&H and Adorama

That's very interesting You can actually see the curvature of field of the lens

From the Exif Data The first three have exposures of 1/13th sec i.e. all the same so the lens is being seen as an f/1.7 : The fast lens is of absolutely no advantage. Canon must have adjusted the ISO?

At f/2 it's 1/8th sec. indicating the aperture from f/1.7 to f/2.0 is being picked up.

The DOF is related purely to the optics and is very shallow at f/1.2 and the sensor is just picking up what's there.

So apart from shallow DOF there's no advantage to an f/1.2 lens :

At the distance these shots were taken there isn't a lot of difference from a visual point of view from f/1.2 to f/1.7 although you can see the DOF change.

Sell them all and buy an A Series 50mm f/1.7 one of the best lenses ever made

It's time the UK made personal imports from abroad easier to stop this mass rip-off. It would save on the pollution caused by shopping trips to the US etc.

Here's how to modify the pin without risking anything
falling into your camera link