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bredman
5th May 2012, 01:04 AM
Time really flies with the OMD manual. :)

It's late, and for a while now i've been trying out the 45mm f1.8 on the OM-D. Everything was fine as i was shooting around the house until a clicking/chattering noise started. I was relieved that the sensor was fine, and these sounds were traced to the aperture ring on the 45mm.

At first i thought it was the angle of the camera as it started while pointing the camera upwards. Afterwards i realised it was only happening when i was catching the lights (3 x 30W) and pressing the shutter half way, and then for several minutes afterwards in a seemingly random fashion, even when not pressing the shutter at all but when the live view was on. The aperture ring was opening and closing randomly and seemed 'loose' but when the camera is off the 'looseness' wasn't evident (i.e. when i tilted the camera the aperture ring 'slid' open and back again, but this doesn't happen when the camera is switched off).

I have found reference to chattering apertures with the Panny 25mm 1.4(?).

Should i worry that the lens is faulty and a more serious problem may be lurking (the images are fine right now)? And has anyone else noticed this issue with the 45mm (i put the 12mm back in and tried to replicate the issue, but the 12mm seems aok)?

Any info appreciated. :)

snaarman
5th May 2012, 06:50 AM
I have noticed the 45mm seems to screw its eye up if the scene is bright enough. Its as if it needs to stop down to keep the live view within the brightness range of the display or sensor.

Alos, If you look into the lens, it might be looking past your head at the sky or an indoor light , so it does stop down or open up depending on what's in its field of view.

I don't think it's a fualt, however it may have an unexpected consequence. The camera might currently need the lens to be f4 while you are in live view, but you have demanded f2.8 for the picture. So when you press the DoF preview button, the lens might actually open up rather than stopping down as you would expect...

Pete

EDIT. I just thought I would check my facts by trying the 45mm on the E-PL3 and then on the E-M5. It seems it isn't doing this trick on either of them today. I have seen it in this mode though...
Bit of a mystery, it may only happen in special circumstances - so it needs further examination.
I bet there will be a firmware update to deal with it. I doesn't affect the images however...

bredman
5th May 2012, 04:00 PM
Thanks for that Pete. Much appreciated. :)


If anyone has anything further to add i'm very interested.

DekHog
5th May 2012, 06:03 PM
This is quite a common thing with m43 and isn't a fault with anything - my 20mm does it all time when the light varies quickly from bright to dark, and other lenses on certain bodies seem quite prone to it.

I can get it to do it consistently indoors by pointing the camera at a window then quickly pointing it back inside the room again. Between chatter (20mm) and hum (E-M5) I'm nearly going deaf! Still wouldn't swap it for anything else though. :D

AdamThirtle
5th May 2012, 09:29 PM
I drove me mad when I first realised the 45mm did this, but then I just got over it. It's nothing too bad and is perfectly normal. Be nice if the aperture could just stay open though

snaarman
7th May 2012, 08:26 AM
I have gone looking for this clicky aperture feature, and the best I can say is that it does it some times, and other times it doesn't ..

I also found another odditiy. I was investigating movie yesterday (no, I don't think I will bother) and I turned the dial from movie back to "A" and the IS went all wobbly on me. Where a half press of the shutter should make the image go stabilised and stationary, it caused all sorts of wandering around. I turned the camera off then on again and all got straightened out.

I predict a short flurry of firmware tweaks to the E-M5. You have to remember you are actually holding a microcomputer that happens to take pictures. I suspect the code in there is quite complex and I would expect some bugs and features this early in the game. Well if I had written the code there would be bugs all over it, that's all I'm saying :)

PeterBirder
7th May 2012, 10:46 AM
I wonder if this is a feature of Olympus m4/3 cameras rather than the lens. The dpreview of the Panasonic 20mm f1.7 from Sept 2009 notes this:

"One oddity we did notice is that, while Panasonic's G-series cameras hold the lens's aperture wide open while you're viewing the scene in record mode, the E-P1 has a habit of stopping down, presumably to regulate the amount of light reaching the sensor. This obviously increases the depth of field in the live view image, which can potentially lead to inaccurate manual focus when shooting at large apertures (exacerbated by a false impression that manual focus is easily obtained). Fortunately this behavior can be countered by assigning depth of field preview to the function button, and using it to force the camera to open the lens up to maximum aperture for manual focus (just hope you don't need to set a custom white balance, which also requires the function button, at the same time)."

Not sure if this is the answer but sounds to be related.

Regards.