Minolta 50mm f/1.7 + A900

[soken]

is it possible that u use point metering mode?

 

[TME]

Which version of the 1.7 is it? If it's the newer RS, it should have the chip that communicated metering info to the camera. If it's the classic version, it would explain a lot...

Should be the classic version. It has a metal barrel with the hood as a sleeve or something like that... the metering is ok for other apertures... What's the beef with the classic version?

 

[TME]

If you would shoot in Manual mode, all these problem is no longer an existent. It only happen if you decide to let the camera take control on how the exposure should looks like.

Lets face it, the metering is always not the best given any camera on all situation. If you want to take control, shoot all manual and you will be glad.

Hart

The metering by the camera should be same under identical lighting. I took the two images less than 20s apart indoors. So the change in aperture should be compensated by the shutter speed. Manual mode is not a good comparison cos you can shoot whatever setting you like, which is good if you are really shooting... I was testing the lens so I need some constants to find out the variable.

 

[Agetan]

The metering by the camera should be same under identical lighting. I took the two images less than 20s apart indoors. So the change in aperture should be compensated by the shutter speed. Manual mode is not a good comparison cos you can shoot whatever setting you like, which is good if you are really shooting... I was testing the lens so I need some constants to find out the variable.

Ah... it explains... but still the camera tend to be fool by the different setting even on the aperture... I think it is not unique to 50mm f1.7. Large aperture lens tend to be a little difficult to design for the metering as they then to be fool by the large amount of light coming in. Metering in the camera often the best way to evaluate the real exposure. Metering by light meter will be a lot better if you are going to evaluate something.

Also with aperture, you would need to becareful with the metering mode..... it is very difficult to have 1 setting for all as more often then not, the camera being fool into different scenario.

Hart

 

[Drudkh]

I think the problem here is not about the metering. Refering to the 1st post, TME listed the exposure readings and they are correct (aperture value vs shutter speed). But despite the correct exposure reading from the camera, the image turned out underexposed when aperture is set to f/1.7.

TME, I think you might like to send an email to Sony to address this issue with the 2 photos for reference. I think this could possible be software/firmware problem.

 

[XkaOnslaught]

it could be the 50mm lens aperture blades are stuck at a smaller aperture.? but the camera still registers a bigger aperture and will conpensate the exposure for it?

 

[Rashkae]

TME, I think you might like to send an email to Sony to address this issue with the 2 photos for reference. I think this could possible be software/firmware problem.

Yup. They may ask him to test on a D-version of the 50mm f/1.7, or just ask him to get a Sony 1.4.

 

[TME]

Yup. They may ask him to test on a D-version of the 50mm f/1.7, or just ask him to get a Sony 1.4.

How about a 1-1 exchange?!:sweatsm:

 

[Drudkh]

How about a 1-1 exchange?!:sweatsm:

Or you try to borrow another copy of 50mm 1.7 and A900 to test?
One more question, have you tried using the same setup with the toy bear and shoot in another location with a different lighting?

 

[TME]

Or you try to borrow another copy of 50mm 1.7 and A900 to test?
One more question, have you tried using the same setup with the toy bear and shoot in another location with a different lighting?

Nope, haven't tried. Will try again today when I get home... I think might be the same result... I'll shoot a range of apertures today.

 

[TME]

Ok folks!!! Here's the show...

Shot at ISO3200, f/1.7, 2, 2.8, 4, 5.6 & 8...

Definitely shows very clearly loss of exposure at f/1.7 and even at f/8... exposure is the same for all other apertures... why?!

Down-ressed shots below... out of camera jpegs. X.Fine. No pp at all. 1024x 683 px dimensions.

 

[TME]

f/8, 1/20s, ISO3200, A priority, no flash. Centre-weighted metering. Centre AF sensor. On tripod. Triggered by remote commander.

 

[TME]

f/5.6, 1/30s, ISO3200, A priority, no flash. Centre-weighted metering. Centre AF sensor. On tripod. Triggered by remote commander.

 

[TME]

f/4, 1/80s, ISO3200, A priority, no flash. Centre-weighted metering. Centre AF sensor. On tripod. Triggered by remote commander.

 

[TME]

f/2.8, 1/160s, ISO3200, A priority, no flash. Centre-weighted metering. Centre AF sensor. On tripod. Triggered by remote commander.

 

[TME]

f/2, 1/320s, ISO3200, A priority, no flash. Centre-weighted metering. Centre AF sensor. On tripod. Triggered by remote commander.

 

[TME]

f/1.7, 1/400s, ISO3200, A priority, no flash. Centre-weighted metering. Centre AF sensor. On tripod. Triggered by remote commander.

 

[TME]

It might be easier to compare this way... a screen capture of my photobucket folder.

From left to right: f/8, f/5.6/, f/4, f/2.8, f/2, f/1.7

 

[XkaOnslaught]

it looks to me more like a loss in contrast. rather than exposure problem...

 

[XkaOnslaught]

also, look here.

http://kurtmunger.com/minolta_af_50mm_f_1_7_reviewid114.html


seems like vignetting of the lens is the issue here. the F1.7 and F2 crops seemed darker.