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05-15-2014, 01:51 PM   #1
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Super Wide II, canīt handle f2.8

Hi, I have a Sigma Super Wide II AF. The thing is that I have had this for some time and used it a bit. I would like to sell it and nearly did to a fellow member some time ago.

He kindly returned it with the message that the camera can't handle f2.8, it reads it though.

The lens is in pristine condition and it is a pity, that it is on the shelf most of the time.

Do any of you know of this problem and would it be interesting to have a lens with this problem?

Thanks

05-15-2014, 02:05 PM   #2
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You say you used it in the past. Can you use it now? Is the problem only something reported by someone else, or is it something that you've noticed yourself?
I had a Sigma 24mm Mini-Wide AF, which was working perfectly fine at all apertures. I don't know what that could mean, "camera doesn't handle f2.8 with the Sigma 24mm"...
05-15-2014, 02:22 PM   #3
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QuoteOriginally posted by causey Quote
I don't know what that could mean, "camera doesn't handle f2.8 with the Sigma 24mm"...
I don't know what it means either. Having owned two of these, I know the IQ is weak at f/2.8 (in fact, it's weak all the way to about f/4) but it certainly works. Personally, I consider this a good enough reason not to want the lens, but what does he mean by "the camera doesn't handle it?" It sounds almost like his particular camera wouldn't open the lens up to f/2.8 - is this the case?



But if he was only referring to the IQ at f/2.8, that's just a characteristic of this lens. Some buyers might not like this, but it's just the way they're made - it's not a defect.

So as long as it takes some kind of image on your camera at f/2.8, and has reasonable IQ at around f/4 and beyond, you should have no hesitation is selling it again. Some people really like this lens - let the next buyer decide for himself whether he likes it or not!



As I'm sure you're aware, there is no other affordable AF 24mm lens for Pentax, making this Sigma an attractive option in spite of a few drawbacks it may have.

Last edited by DSims; 05-15-2014 at 02:36 PM.
05-15-2014, 02:30 PM   #4
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My AF Sigma 24/2.8 is superb wide open at f/2.8, as was the manual focus version I had before it. I never had any problems using it at that setting and can't imagine what it might mean if he says the camera can't handle it.

05-15-2014, 02:44 PM - 1 Like   #5
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Mine has sometimes had contact issues, but it is the manual focus KA mount. It sometimes thinks it can only open to f4. A quick wipe of the contacts and it's back to f2.8. An AF lens uses the contacts differently, and the problem sounds different, but I'd look at the contacts. It's old enough to expect that.
05-15-2014, 02:53 PM   #6
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QuoteOriginally posted by Jonathan Mac Quote
My AF Sigma 24/2.8 is superb wide open at f/2.8, as was the manual focus version I had before it. I never had any problems using it at that setting and can't imagine what it might mean if he says the camera can't handle it.
I'm fairly picky; I've owned or carefully studied every lens in your signature. I no longer have any of them because I've opted for something I think is better.


The point is not that you should agree with my picky standards, it's that there are others like me, and I suspect this buyer was simply one of them.



Moreover you're absolutely right - many owners say it's an excellent lens, so he should sell it to someone else who will appreciate it!

---------- Post added 05-15-14 at 02:58 PM ----------

QuoteOriginally posted by Just1MoreDave Quote
Mine has sometimes had contact issues, but it is the manual focus KA mount. It sometimes thinks it can only open to f4. A quick wipe of the contacts and it's back to f2.8. An AF lens uses the contacts differently, and the problem sounds different, but I'd look at the contacts. It's old enough to expect that.
That is, he should sell it after cleaning the contacts (good idea Dave)!
05-15-2014, 11:47 PM   #7
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Thank all great feedback.

Maybe I was not clear enough. When the lens is on A setting I can select f2.8 and the lens is fully open. It is the exposure time in Av mode that does not change.
Hence "camera can't handle f2.8".

Somehow the camera does not recognize f2.8, there is no change between f2.8 and f3.5.

The contacts are clean but when I opened the lens to have a look (very carefully and gently) I discovered that a piece of clear tape was placed on the contact between the print plate side and lens! I took it off, but with no change of behavior from the lens.
05-16-2014, 08:24 AM   #8
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QuoteOriginally posted by Pontax Quote
Maybe I was not clear enough. When the lens is on A setting I can select f2.8 and the lens is fully open. It is the exposure time in Av mode that does not change.
Hence "camera can't handle f2.8".
Do you mean you put the lens aperture ring in f/3.5 or F/4 and the camera doesnīt change the shutter speed? Thatīs normal, you should leave the lens in A position at all times and control the aperture through the camera body.

QuoteOriginally posted by Pontax Quote
The contacts are clean but when I opened the lens to have a look (very carefully and gently) I discovered that a piece of clear tape was placed on the contact between the print plate side and lens! I took it off, but with no change of behavior from the lens.
Probably a piece of insulator so that there are no short circuit.

05-16-2014, 07:42 PM   #9
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QuoteOriginally posted by Pontax Quote
Somehow the camera does not recognize f2.8, there is no change between f2.8 and f3.5.
That is only a 1/2 stop - depending on the metering mode your camera is in that may not be enough of a difference to alter the exposure. Spot metering is by far the most sensitive to changes in exposure variables. There is also the possibility the T-stop of the lens is not equal to the F-stop causing the 1/2 stop of difference to be reduced to a 1/4th of a stop.
05-17-2014, 12:36 AM   #10
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I am sure that there is a defect, not big though.
A very competent member of the forum ran some test and found the fault.

I would like to sell it, how will this fault affect the price? Big, small or non?
05-17-2014, 08:33 AM   #11
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I think it should open to f2.8. There are enough of them around so they would have a reputation as only an f3.5 lens. You might have noticed yourself. That means it is either out of adjustment or broken somehow. That means the buyer has to find a repair shop or fix it themselves. That means some risk - the shop says it's too old, they don't have parts or whatever. Or the buyer tries it themselves and ends up with a pile of springs, rings and glass. Risk limits your potential buyers. The lens is not so rare that buyers can't find another copy.

I think right now, the price would have to be 30-40% of the current used price.

I'd take some test shots at all apertures and document the brightness change at each one. Then I'd take shots with OOF highlights at wide apertures to see if you see circles or hexagons. That might be enough to show that the lens opens to f2.8 but is out of adjustment somehow and would need Ev compensation. Then the lens is more marketable.
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