Occasional Over/Underexposure - with steps to reproduce

[dpattinson]

Advertisement (gone after registration)

I believe that I have figured out what is going on with the occasional overexposure on my M8. It appears to be due to the camera cacheing the last measured value prior to the meter passivating. It then seems to attempt to use that value if you take a shot without first 'waking' the meter by tapping the shutter.

 

To reliably reproduce:

1. activate the meter;

2. cover the lens with your hand;

3. wait for the meter to passivate (about 8 seconds or so);

4. uncover the lens and point the camera at a bright scene;

5. take a shot immediately, without pre-activating the meter;

6. look at the amazing white preview

 

I presume you could also cause this by leaving the aperture fully open until the meter passivates, and then stopping down prior to taking the shot - since the camera would have no way of knowing that the lens had been stopped down.

 

If intentional, I assume this was intended to allow a shot to be taken without having to wait for the meter to start up, with the idea that the last measured value would most likely be close to correct. The problem is that the last thing the meter is looking at in many cases is the inside of ones jacket, or the ground, hence the tendency to overexpose.

 

A better solution might be to cache the last measured value that was actually used to take a shot. This would in my experience be much more likely to be near correct than the EV of whatever the camera was pointing at when the meter passivated after 8 seconds of inaction. Of course if the meter is actually able to wake up without delaying the shot - it would be better still to not cache a value and to use the new EV as metered.

 

David.

[ho_co]

Very interesting!

 

And welcome to the Forum, BTW!

 

--HC

[dpattinson]

Thanks HC,

 

I've reproduced this problem on two M8's now, with the latest firmware installed. A number of people have also noted it in response to a post I made in the flickr M8 group. They assumed it was just an occasional glitch or user error - however I'm pretty convinced there is an underlying problem, since it's so easy to reproduce.

 

It seems like it should be pretty easy to fix, how does one get in touch with Leica to report something like this? I took a look on their website, but all the email addresses appear to be for service or sales - there doesn't seem to be an address where you can report a reproducible technical fault.

 

I'd love to get it fixed, because it's a huge pain in the ass for the kind of work I do. I can live with wrong image in review mode, and click wheel skipping - but in this case I miss shots altogether, and if the camera decides that it wants to shoot a 32s exposure because the last thing it saw was the inside of my coat, then I lose double the time due to noise suppression. (Of course, I now hear the shutter open, realise what is happening, and flick the shutter wheel to 8000 - but that still means a few seconds of no shooting).

 

David.

[andybarton]

Drop a PM to Guy Mancuso on this forum. He has an inside track to Leica and has been bringing forward issues such as this and getting resolutions to many of them.

[Riley]

i think almost any digital i have had would do that

its not giving the metering time to adjust

[jaapv]

Not just any digital, any camera needs a fraction of time to allow the meter to measure and the electronics to calculate. I don't think this is a bug, just a basic fact of photographic life....It happens when using the Visoflex too fast too. On the M7 it is the same. The simple solution is to use the camera on manual, which, in my experience, is easier and better anyway.

[dpattinson]

Advertisement (gone after registration)

Riley,

 

It seems odd to me since my M7 has no such problem, I'd assumed that the 'wake-up' time for the photocell in the M8 would be the same as the M7. I therefore think that the problem is actually a cached value, which should have been 'marked dirty' when the meter passivated (to use a programming term).

 

I know the metering used to passivate in the film cameras to save battery power. In the case of the M8, I suspect the battery drain due to metering would be trivial compared to processing files and chimping. In this case I'd rather have an option to disable the meter passivation, so that the meter is on while the camera is on.

 

I tried PM'ing Guy - but his message storage limit has been exceeded

 

I'd be interested to hear if anyone can reproduce this issue (or if they cannot, following the steps I listed above).

 

David.

[dpattinson]

Jaap,

 

Not a problem with my M7, which I use in precisely the same way. Nor with my Konica Hexar RF for that matter.

 

I have never seen an inappropriate long exposure on my M7, and by inappropriate I'm talking seconds when it should be fractions.

 

<edit - I just tried to reproduce on my M7, using the steps listed above - doesn't happen>

 

My conclusion is that either it's an unavoidable issue with digital cameras - which I really hope is not true, or that there is a cacheing/timing issue with the M8 when waking the meter. If it's the latter then it probably should be fixable - even if only by leaving the meter on all the time.

 

It might not be clear, but I'm talking about this happening on the first shot every time the meter passivates, not only when the camera itself switches off due to 5-10 minutes of inaction.

 

This means that if you take grab shots in the street, pretty much every shot you take is affected, unless you develop ticcomania of the shutter finger to keep the meter active

 

David.

[jaapv]

David, I had the wrong exposure problem on the M7 with the Visoflex, so I assumed it was the same with the situation you describe on the M8, which does indeed give whiteouts when used fast in that way. I use the Visoflex for wildlife, and reverted to manual for exactly the same reason. Alternately I release consciously in two steps, giving the camera the time to adjust. Maybe using manual could be an interim solution?

[dpattinson]

Jaap,

 

I've been using manual as a workaround, which in some situations is better anyway if the lighting is not uniform. I'd gotten out of practice since having the M7 though - so I suffer the same issue (but self inflicted) when the light changes and I don't remember to reset the exposure.

I have also started tapping the shutter as I raise the camera to activate the meter before I get it to my eye - but that's kind of irritating and certainly is a case of the camera 'getting in the way' of the photographer.

 

Hopefully it will turn out to just be a matter of ensuring the meter has woken up before the camera accepts the reading. I'd prefer not to have to remember to pre-activate the meter every time I want to take a quick shot.

 

David.

[Guest guy_mancuso]

I'm here and my inbox has been cleared out, sorry i was on the road. i will send this in but from what i remember is the meter will hold for 12 seconds and it maybe you have to reactivate it again, not sure but will forward this to Leica. Thanks