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01-23-2015, 05:37 PM   #16
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This copy of Bigma works great on my k-5 and k-3 but doesn't cut it on the Qs.
Your 170-500 looks to be a good performer.

01-23-2015, 05:59 PM   #17
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Crewl, yeah I've finally got a keeper lens.......allot of times I get duds.....I lucked out with this particular lens.......even at 500mm on ff it's reasonably sharp wide open and only needs to be stopped 1 click to really sharpen up.
(I still want to test a Sigma 50-500 on my Q7- maybe I'll get lucky 2x!)
01-23-2015, 06:29 PM   #18
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QuoteOriginally posted by crewl1 Quote
This copy of Bigma works great on my k-5 and k-3 but doesn't cut it on the Qs.
Your 170-500 looks to be a good performer.
I don't understand why it works great on K-mount but is mediocre on Q-mount. I would expect it to be the other way around if anything. Do you think the handling of aperture (not using internal system on Q-mount) has anything to do with it?
01-23-2015, 09:03 PM   #19
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Don't see why that would be true with any lens. Larger photosites are pretty much always going to equal greater apparent sharpness, at least at the center of the lens - the edges might be a different story, since the smaller sensor effectively crops off soft edge zones. Very few zoom lenses can resolve down to the absolutely tiny size of the Q sensor pixel sites. The A actuation lever and the aperture ring are going to give you the exact same aperture for any specified F-stop value (the actuation distances follow a standardized formula for all K mount auto aperture lenses) so not sure how that would have any bearing either.

Getting back to the original comparison between the 170-500mm and the Bigma, it simply seems that the 1570 is sharper at certain lengths, particularly toward the long end. Although the Bigma and the 150 are often called siblings, their designs are different in both numbers of elements and groups, so their performance profile isn't necessarily going to be the same at similar apertures or at different points in the zoom range. Compromises increasingly have to be made the longer a zoom range you put into a lens, and it appears that in the Bigma's case, sharpness at full zoom appears to be what was sacrificed. I've used 3 copies of the Bigma, and in every single one, sharpness falls off rather drastically between 450 and 500. I've not used the 170, but it seems that it doesn't suffer from the same problem. The extra bucks you pay are for the better overall zoom range and maximum aperture, but that doesn't mean it stands to reason that it will perform better in all configurations.

QuoteOriginally posted by reh321 Quote
I don't understand why it works great on K-mount but is mediocre on Q-mount. I would expect it to be the other way around if anything. Do you think the handling of aperture (not using internal system on Q-mount) has anything to do with it?


01-23-2015, 09:45 PM   #20
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QuoteOriginally posted by reh321 Quote
I don't understand why it works great on K-mount but is mediocre on Q-mount. I would expect it to be the other way around if anything. Do you think the handling of aperture (not using internal system on Q-mount) has anything to do with it?
DCshooter explained it more expertly, so all I will say is the Q sensor is brutal in exposing faults in lenses.
You can see examples in the Adapted Lenses sticky thread of lenses that owners rave about on their K cameras but look quite poor on the Q.
The Q7 is a little more forgiving since it uses a larger sensor with the same MP count vs the original Q.
01-24-2015, 06:50 AM   #21
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Great reply DCS~
Found someone with a nearly new 50-500 (Minolta mount) and offered to pay their asking price- now if I get to meet up and purchase the lens- tests will be coming!
I'm really looking forward to seeing how this 50-500 stacks up against the 170-500 at identical settings.
Cheers everyone~~~~

Last edited by SteveNunez; 01-25-2015 at 12:23 PM.
01-27-2015, 04:21 PM   #22
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Hello guys, I've recently acquired what appears to be an absolutely mint Bigma for Minolta mount which I intended to test with the Pentax Q7..........problem is, if I try to manually focus the ring is very stiff as if the lens' weight is holding the ring from turning smoothly.....if I slightly lift the lens a little with the other hand the ring spins much easier- the rear also has a little wobble to it..........what do you guys think?

I purchased it from a woman who met me at a Barnes & Nobles and as soon as I paid her- she basically left the store in a hurry............starting to think the lens may have been dropped while in the protective case and thus why it looks 100% mint but has a wobbly rear (where tripod collar is).....does anyone else have an issue with their Bigma when manually focusing or did I just get ripped off?

Sad- was going to photograph my daughter's baptism with the lens.

Anyway it is what it is.......let me know what you guys think about this Bigma.
(The AF works fine on my Sony A7)
01-27-2015, 04:47 PM   #23
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The manual focus on my unit is easy and there is no wobble. It sounds like it may have been damaged, unfortunately.
In AF does it work fine otherwise?

01-27-2015, 05:05 PM   #24
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Yes- the AF is perfect.......on this Bigma there's a push-pull clutch for AF/MF and in MF it works but is stiff as the assembly wobbles a bit and the weight stiffens the lens ring.........if I lift slightly (the body,) the MF is MUCH better- my guess is that I have to send it to Sigma for repair.
The lens is absolutely MINT- looks 100% new..........I think it may have been dropped while in the protective bag and got misaligned internally.

I will call Sigma tomorrow in NY and request a repair and estimate- i just hope it's not over $300 and takes months!
01-27-2015, 07:26 PM   #25
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Ugh, that's too bad. Might be as simple as tightening some screws inside the unit, but it's bound to be expensive if you have the OEM repair it. A thread on dpreview (I saw yours, too!) from 2007 mentions $180 for the repair, so I'd imagine it's more like $250-$300 today.
01-27-2015, 07:41 PM   #26
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I too think it's just loose screws......is it straightforward to tighten these screws?
01-27-2015, 07:52 PM   #27
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I've not yet pulled apart a Bigma, but looking at my own copy (EX DG, non HSM), if you pull back the rubber grip from the focus ring, it looks like there are several screw access holes. It might pay to take a look through them (you might have to move the ring through various positions) and see if you can find any screws that appear to be loose. If the AF works fine, it seems like the issue might lie with where the outer and inner mf focus rings mate.


Maybe you can get in touch with this guy for further enlightenment.


QuoteOriginally posted by SteveNunez Quote
I too think it's just loose screws......is it straightforward to tighten these screws?
01-27-2015, 08:20 PM   #28
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Going to take a look at that rubber focus ring, didn't know it could be pulled back.....many thanks for this reply!

Ok- checked and pulled the rubber ring back....saw a few silver tangs and tiny screws-all look perfect, I guess adjustments are internal.

Last edited by SteveNunez; 01-27-2015 at 08:51 PM.
01-27-2015, 08:30 PM   #29
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QuoteOriginally posted by SteveNunez Quote
Hello guys, I've recently acquired what appears to be an absolutely mint Bigma for Minolta mount which I intended to test with the Pentax Q7..........problem is, if I try to manually focus the ring is very stiff as if the lens' weight is holding the ring from turning smoothly.....if I slightly lift the lens a little with the other hand the ring spins much easier- the rear also has a little wobble to it..........what do you guys think?

I purchased it from a woman who met me at a Barnes & Nobles and as soon as I paid her- she basically left the store in a hurry............starting to think the lens may have been dropped while in the protective case and thus why it looks 100% mint but has a wobbly rear (where tripod collar is).....does anyone else have an issue with their Bigma when manually focusing or did I just get ripped off?

Sad- was going to photograph my daughter's baptism with the lens.

Anyway it is what it is.......let me know what you guys think about this Bigma.
(The AF works fine on my Sony A7)
Steve, I would send it to Sigma for a check over and necessary repairs. A few year ago my bigma got damaged when I took a bad fall. I sent it in telling them that it had been dropped, they sent it back better than new and NO charge.
01-27-2015, 08:53 PM   #30
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Heinrich, will call them tomorrow.

On a side note, I saw a listing on eBay for a used one where the fellow stated the lens was too old for Sigma to repair thus he was selling for parts.....does that sound correct- a lens too old for Sigma to repair?
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