Old Lens Underexposes

[baltdave]

Hi,

I bought a used 135mm EF 2.8 SoftFocus lens on eBay for a reasonable price.  If I am reading the date code correctly, the lens is nine years old.  The lens focuses fine and works fine, but there is one problem, when I shoot pictures with that lens, the metering seems to underexpose by almost a stop.  This doesn't happen with any of my other lenses (all of which I bought new). 

The underexposure happened on both of my bodies (5D Mark II and T2i).  Any advice on what to do to correct the problem?

Thanks for your help.

[Drizzt321]

Look through it, do you see any haze or anything? If it looks fine, you can always try and send it to Canon for cleaning, or just go ahead and set the metering to +1ev when using that lens.

[brad goda]

does the under exposure happen in non soft mode? set 0
or does it vary with the soft function activated... then if so does it get darker with  SET 1 OR 2?
this lens being pre digital there might be some function anomalies translating to camera...
like using any TSE lens just forget reading the meter as you actuate ANY of the tilt or shift functions...
bending the projected image whacks the sensor silly...
if ev diff is consistently -1 then just knowingly adjust...
do you like the soft effect? how does it look... does it create CA?

[paul13walnut5]

This is a funny lens.

I got duped into selling mine for a fault, for next to nothing.

1.  Look through the lens.  If it looks as if there is condensation do not panic.  Its the soft optic and not a fault.

2.  Metering will be affected with this lens as it is being bounced about the lens tube a bit rather than focused into the meter.  Use centreweighted rather than spot or partial metering.  And where possible do a test shot.

[baltdave]

Thanks for the advice...I'll try out what everyone suggested and report back.  The underexposure was happening without the soft-focus effect invoked, and it was consistently 1 stop underexposed, so I haven't set exposture compensation...I just boost the exposure in Digital Photo Professional after the fact.

I thought it would be interesting to use the soft-focus, but after using it a couple times, I'm not sure that I will use it that often!  I ended up not liking the effect.

[brad goda]

baltdave...

ha i guess boke boke back ground is wonderful... but for digital...  boke boke subject is subjective and problematic...
ive tried using my old expensive heliopan softar sets and yuck holy $#!† loads of weird CA...!
maybe for digital bokeh boke subject is better made in post.

interesting subject and lens from the past.

[paul13walnut5]

With the effect switched off it's actually a decent performer, if you can live with the afd focusing.

[TexPhoto]

I had a sigma that was over exposing some of the time, almost always by 2 stops.  The problem turned out to be a stuck aperture that would only close down to 5.6.  So if you needed 2.8, you got 2.8, need 5.6, you got it.  need f8? you got 5.6.  need f11, you got 5.6.

Any way new aperture fixed the problem.

And 9 years is not old.

[paul13walnut5]

And 9 years is not old.

Even though the sample was manufactured 9 years ago, the design dates back to the birth of the EOS system, October 1987, so the technology at work is going on 26 years old now.  Witnessed in the facts that it's no longer a 'fashionable' effect, and that the focus motor takes about a week to slew from close to infinity.

[Mt Spokane Photography]

I just reviewed my images with this lens from back when I had it.  I used a 400D at that time.  Exposure was perfect on all of them, no adjustment required.

[baltdave]

Thanks for everyone's help and suggestions.  I cleaned the contacts on the lens using a pencil eraser and isopropyl alcohol and a q-tip and it seemed to solve the problem!  I was pleased with the results!

Thanks again.