blackest Loc: Ireland

You are confusing me or is that me, I didn't mention focus Although Canon expects to focus wide open it's up to you when you are using a manual lens, although you might struggle to get the camera to confirm focus at an f-stop higher than around f5.6.

With metering this is also done wide open normally metering the reflected light. Say with a 2.8 lens it calculates say f2.8 1/500th at iso 100 and if you dial in f4 it adjusts the shutter speed to 1/250th and f5.6 1/125th. it doesn't calculate the shutter speed when it stops down the aperture in automatic mode, thats too slow and too late the mirror is already up.

The shutter speed it tells you while framing / adjusting focus assumes you are going to the aperture you dialed in.

It really doesnt matter much for a manual lens if the aperture is fully open or stopped down some. if the adapter says its f1.4 maximum aperture on a lens which is f2.8 it doesn't matter that isn't the case. As long as you are saying the aperture will not be stopped down for the shot.

If you tell the camera that you are shooting at f5.6 instead of f1.4 It goes ok this is the value at f1.4 so half for f2 half for f2.8 half for f4 and half for f5.6 so if wide open meters at 1/1000th then 1/500th 1/250th 1/125th 1/60th.

The problem is that you are not going to stop down 4 stops in reality you are already at the stopped down position. The camera doesn't know that. So it uses 1/60th when it should be using 1/1000th and over exposes an unrecoverable 4 stops.

if you just tell it the shot is going to be at f1.4 it will not reduce the shutter speed regardless of the actual aperture set.

If you are using a separate meter to calculate the exposure then set the aperture and shutter speed and iso and the camera will take the shot with your parameters if the exposure is good thats down to your calculations.

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

That doesn't match my experience at all. I'll give a test, .....

Well that didn't take to long...

So I'm using an old Canon T3i in Av (aperture priority mode), with ISO at a fixed setting (400) with an old FDn 135mm f/2.0 lens converted with an Ed Mika adapter with a Dandelion chip. I can get focus confirmation at anything from wide open (F/2.0) to (f/5.6), even with then lens set to f/8 which the camera shouldn't do, and the shutter speed adapts accordingly. The exposures are consistent, except for the changes that result from motion from the different shutter speeds.

So much for theory and experience! In theory the camera should not give focus confirmation above f/5.6, but with this lens set to f/8 it does. Above the f/8 setting it does not. The camera is responding to the available light, not what the settings on the lens say. Simple stopped down metering. However the camera does set the shutter speed accordingly. I have the same experience with other lenses, the FL 55mm f/1.2, Helios 58mm f/2.0 and so on.

Perhaps it is a Canon thing, I don't have other cameras to experiment with. That said the world is a complex thing, maybe my experience is a corner case.

blackest Loc: Ireland

So well exposed with any f-stop set on the canon dial regardless of what it actually is?

Hmm could be a case of what I thought i know , I didn't know. In which case you can set an aperture that reflects the settings used (or not) and that will be recorded in the exif and not effect the cameras exposure calculation.

Sorry if i have misled anybody.

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

A manual lens cannot communicate the actual aperture used unless there is electronic communication, but the lens details can be recorded, and the exposure values can work effectively. The actual aperture used is not recorded in the the view finder, nor in the EXIF data, the lens ID can be, but the exposure can be good and it is the camera that controls and records the shutter speed, ISO and so forth. So other than actual aperture setting everything else is good. Unless notes are made - the old school way - the actual aperture can be deduced to some degree from examining the image if desired with some kind of visual interpretation.

We both agree I believe, the camera cannot record information that is not communicated, but the exposure calculation can still be 'correct' according to the meter. I have had no problems with exposure, but the EXIF has no record of the actual aperture used, but I know the rest. The only lens where I do know the aperture used is a fixed aperture reflex lens, but if I add a neutral density filter there is no way to record that.

So this is a Canon FDn 500mm reflex lens, aperture f/8.0, shutter speed 1/1000, ISO 400. Camera was a T3i. What else do we need to know?

graybeard

I did not mean or intend to confuse exif with exposure. As long as I have my camera's aperture set low, I can get a good exposure with the shutter speed and iso of the camera and the aperture of the lens in proper balance, as measured by the meter. No problem, or question there. What I wanted was exif info that would tell me what manual lens I was using, as the lowest aperture and lens focal length combined would be unique to my lens roster. I am beginning to wonder if such largely esoteric information is worth the aggravation I am having getting these things "programmed" !!

blackest Loc: Ireland

Often a notepad and a pencil is enough, one of my cameras lets me put photographer info at one point i put manual lens info there instead, till i decided it wasn't worth the effort.

CHG_CANON Loc: the Windy City

I use an EXIF editor and add the data into the image files as part of my post processing.