First of all, a happy July Fourth to our many American and Danish readers. It’s a good day to talk about taxation and representation, in this case, representation of our camera EXIF data. And, since we don’t have a holiday today in the UK, I am able to sit behind my computer and pound our yet another post for Macfilos.
One of the problems with using manual lenses, and I’m thinking mainly of M-mount lenses, with mirrorless cameras is the lack of aperture values attached to an image. It can make future reference something of a hit-or-miss affair and, as a writer, it is very inconvenient not to be able to quote aperture values for published images.
Sadly, this problem has been extant even with the Leica rangefinder in recent years. M-mount lenses are as dumb as they come, so there is no electronic jiggery-pokery available to populate the EXIF data.
Fortunately, Leica has produced a solution, a way of estimating aperture settings with reasonable accuracy. This isn’t new, of course. It used to happen with the M9 and the M240 but the facility disappeared when the M10 came along. I have example images from the M9 in 2012 which clearly show an aperture value. I also remember Leica announcing they had withdrawn the facility on the introduction of the M10 because it was not of any great use. I disagreed at the time and I’m glad they have now had second thoughts.
So how does it work?
Leica tells us:
“The camera compares the brightness measured through the lens with the measured ambient brightness to estimate the aperture used. This value is then written to the EXIF data. In some cases, the interpretation of the subject or scene may lead to incorrect estimation of the aperture value, for instance when shooting subjects or scenes with high contrast and black or white objects.”
This is intriguing and, of course, the potential problems in unusual circumstances are easily understood. Overall, though, the system gives a much better estimate of aperture than we can achieve by sight — perhaps checking the amount of bokeh in relation to the lens focal length. It’s hit or miss and I wouldn’t have the confidence to pontificate on the subject.
The new facility included with the latest M10 firmware is thus of great practical value to all photographers and I am really pleased that it has returned. In real terms, the calculated value is good enough.
Interestingly, the semi-intelligent manual lenses made for the Sony E-mount — such as the Voigtländer 40mm Nokton and 65mm Apo-Lanthar transmit accurate aperture values because of the electronic connection. And as I touched on yesterday in the motorcycle article, they are also able to initiate focus aids by detecting movement in the focus ring. The M10 (and all digital Ms) can also do this thanks to the mechanical focus linkage for the rangefinder.
I am grateful to William Fagan for pointing out that the M240 also reported estimated aperture and that it was only when the M10 was introduced that the facility was deleted. I’ve amended the above text to reflect this fact and I’m sorry for any confusion.
- Subscribe to Macfilos for free updates on articles as they are published
- Want to comment on this article but having problems?