All the cameras I've tested (ongoing) give pretty much the same exposure at the ISO and aperture settings, but it seems different cameras need different shutter speeds (Av Mode where the variable is shutter speed), where possible the same (Pentax 50mm f1. lens was used. There is no sign of burnt out to white or blocked out to black pixels in any of the exposures.

I would agree that I need to set up a target with a known exposure value, may be an evenly lit mid grey screen so there is no variation in the tones that each camera may be seeing, but all the cameras were looking at, as near as I could, the same frame.

If you can see this image you can upload from your hard drive, you may have to be a member to do it, when you click on the 'Image' button you should get a screen that enables you to Browse your computer, there will be restrictions on the size of file you can use I would think.

The test was done in Live View, though I hadn't thought of that.

Good point, but if I put my K to Q adapter on the Q and use the same lens on both cameras I get exactly the same result, pretty sure it's differences in the sensors, it's the only thing I can think of.

Has anybody else noticed this? If I put my K5 and Q cameras side by side, both in Av(Aperture Priority), framing the same shot, both with the same aperture and ISO the shutter speed on the K5 is twice as fast as it is on the Q, or 1 f stop.

The real surprise came when I checked my friends Canon 5D which was two stops slower!! The same as Sony (with their semi-silvered mirror robbing you of 2 stops), the K-01 and the Nikon D7000 were both the same shutter speed as the K5.

Is this just a one off? Has anybody else noticed this phenomena?

It means that if you shoot in low light, don't buy a Canon and you can use 2 stops smaller apertures on a Pentax (forgetting the DOF differences) and get the same shutter speed as a Canon which is quite a saving on wide aperture lenses.

No wonder the K5 has such a good low light performance. We should shout this from the rooftops.

At last!! I have some decent light to re-do these shots, this time outside, not through double glazing.

Same setup as before Skywatcher 127 Muskatov Cassegrain telescope an f4 1500mm lens effectively, with the 5.5 crop factor giving the equivalent of an 8250mm lens.

Pic 01




Pic 02




Pic 03

The view from the back of the scope taken with the 01 8.5mm kit lens showing roughly the areas covered by the scope Q combination.




Chris

Looks like I got the last one - I hope.

They've just accepted my order for one (literally 5 minutes ago)and it says 'in stock', I'll wait and see.

I realise this is an older post, but I just noticed Jessops are selling the Pentax O-VF1 External Viewfinder for £19.99.

http://www.jessops.com/online.store/categories/products/pentax/o-vf1-external-vi...

Next on my list, but at this focal length I will only be able to get a little of it in the frame.

I know, but it's raining outside LOL

It's a Skywatcher 127 Muskatov-Cassegrain telescope so it's 1500mm X 5.5 crop factor so it's effectively an 8250mm lens.