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10-16-2011, 08:23 PM   #16
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I had a 150-500mm HSM OS for a couple of weeks but sent it back because I was not happy with the sharpness at 500mm. It just did not hold up for cropping. I was also disturbed by the size, the zoom creep and the rings that turned opposite to all my Pentax lenses.

Shutter speed, ISO and aperture are a constant battle with any supertele. I tried to maintain at least f/6.7 with the Sigma because it was too soft at 6.3. F/8 is of course better, if you have enough light. 1/350s is reasonable, that's only one stop down, but not so good if your subject is in constant motion. When possible, I tried to keep the K20D to ISO 560 or lower and the K-x to ISO 800 max. The K-5 would be comparable at ISO 1100. Unfortunately even ISO 1600 is sometimes not enough to maintain a decent shutter speed.

With a K-5 and 150-500, I would run the ISO up to 1100 before I'd let speed drop below 1/500s. I'd go down to 1/250 or even 1/180s before I'd close down from f8. But really, there's no hard and fast answer. I would not shoot without OS unless you're on a tripod. It really does work and my tests showed it was more effective than SR at 500mm. OS can't compare to a tripod, but most of my shooting does not include a tripod.

I now have a Pentax A*300mm f/4, which I use with a Kenko 1.5X Teleplus TC for birding. This combo is definitely sharper than the Sigma but of course no AF. I believe it's as long as the Sigma too. The Sigma is an internal focus lens, and loses range at distances closer than infinity.


Last edited by audiobomber; 10-16-2011 at 08:33 PM.
10-16-2011, 10:18 PM   #17
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Have you checked your SR settings? SR + APO?? I know if I have my SR set wrong (24 or 28mm) then I throw on a 300mm lens and forget to change it's setting it sure can mess up my IQ... I now usually turn it off in decent light, or if I'm shooting with my old beast 400mm 6.3 that is useless until F8 or F11.
10-17-2011, 04:47 AM   #18
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QuoteOriginally posted by Chex Quote
Have you checked your SR settings? SR + APO?? I know if I have my SR set wrong (24 or 28mm) then I throw on a 300mm lens and forget to change it's setting it sure can mess up my IQ...
The camera reads the Sigma's focal length automatically, you don't input the value. That doesn't matter anyway, since it's best to disable SR and use OS.

Good point though. I forgot to disable SR a couple of times, and that does cause soft photos.
10-17-2011, 05:32 AM - 1 Like   #19
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I have been shooting with the Bigma (50-500mm non OS) for almost two years now. There was a learning curve with it.

here are some things I most always do when shooting with the Bigma.
1. Always use a monopod
2. Use TAV on my K5 (I set aperture and shutter speed and the camera sets ISO for exposure) I would like to keep the ISO below 1600 but sometimes nature does not cooperate.
3. Set shutter to 1/750 and aperture to f8.... F11 if it is bright and sunny.
4. I keep the SR turned on even for monopod. (turned off for tripod)


I get similar results to yours at times. It generally happens when I take a similar shot of a Egret at 3-400 feet and then crop it. I have found that even with 500mm to play with, your results are still much better if you can get as close as possible. When I first got this lens, I was trying to take pics of birds and animals 2 kilometers away and was never happy with the results. Winter set in and I started taking pictures out my of backyard birds on our fence at about 10 ft and the results were great. I then realized that the closer I can get the better. Also, the brighter the light, the better for that lens. It seems to really help capture more details.

good luck with your lens.

10-17-2011, 06:29 AM   #20
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Was the engine on? I find that turning off the engine makes a huge difference when using the car window for support at longer focal lengths (possibly due to the shake reduction getting fooled otherwise).

Also, even a little wind can cause a car to shake, so with 500mm f/l you should probably use a shutter speed of 1/500 or shorter (if you're a shaky fellow like me, at least ).

QuoteOriginally posted by MetteHHH Quote
Thanks Alberts. I'm perfectly alright with a shallow DOF though - in fact in a motive like this, I would prefer the surroundings to be out of focus. I only stopped down to f6.3 to see if I could improve the sharpness a bit... but it didn't really work out.

True that with this lens I find the bokeh a bit ugly, but too much depth would detract attention from the bird. Anyway ugly bokeh is the least of my worries, if only the bird would be a bit sharper...

BTW: I didn't use a tripod, but I did use a car window for support.
10-17-2011, 08:46 AM   #21
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Looks a little suspect compared to my experience with 170-500. But don't expect perfect images at 500mm. Sample on monopod at 1/500 while on a boat


QuoteOriginally posted by MetteHHH Quote
... I had the lens OS active and supported it on the car window frame. ...
A couple of silly questions, please don't take offence:
- Was the SR off while the lens OS was active?
- Was the car off?
- Was the wind blowing (it could be vibrating the car slightly)?

Why not try a few static beach-marks to see if everything is working fine under ideal conditions. Tipod, static subject, remote or delayed release, SR/OS off. And then work from there.
10-17-2011, 09:10 AM   #22
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QuoteOriginally posted by GaryH Quote
I have been shooting with the Bigma (50-500mm non OS) for almost two years now. There was a learning curve with it.

here are some things I most always do when shooting with the Bigma.
1. Always use a monopod
2. Use TAV on my K5 (I set aperture and shutter speed and the camera sets ISO for exposure) I would like to keep the ISO below 1600 but sometimes nature does not cooperate.
3. Set shutter to 1/750 and aperture to f8.... F11 if it is bright and sunny.
4. I keep the SR turned on even for monopod. (turned off for tripod)


I get similar results to yours at times. It generally happens when I take a similar shot of a Egret at 3-400 feet and then crop it. I have found that even with 500mm to play with, your results are still much better if you can get as close as possible. When I first got this lens, I was trying to take pics of birds and animals 2 kilometers away and was never happy with the results. Winter set in and I started taking pictures out my of backyard birds on our fence at about 10 ft and the results were great. I then realized that the closer I can get the better. Also, the brighter the light, the better for that lens. It seems to really help capture more details.

good luck with your lens.
Pretty similar to my experience with 150-500 and K-7 - although obviously I don't have the same ISO latitude
10-17-2011, 09:32 AM   #23
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I think this will be easier solved if you just send me the lens for QC checking purposes...

10-26-2011, 04:50 AM   #24
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I would like to thank you guys very much - you have been absolutely brilliant!

The main thing this thread did was relieve me of my iso-anxiety. I upgraded to k5 mainly to get less high-iso noise, but I was still afraid to go over iso 800 - when in fact I should have feared the max aperture of my Bigma and motion blur a lot more. TAV makes SO much sense, and it is my program-of-choice for bird shots from now on!

(I'm particularly baffled by the difference it makes to use f8)

This is more like it, right (f8, 1/500s on TAV):
http://dl.dropbox.com/u/10485935/Gr%C3%A5g%C3%A6s.jpg

mickey: You might be right about the legs of the egret being sharper than the eyes, and I should do a careful and systematic investigation of the need for focus adjustment. I just didn't get around to it yet (tried a bit of trial-and-error-adjusting, but that didn't help).

audiobomber: I have a Pentax 1.7 converter with AF, and eventually I would love to combine that with a DA* 300mm f4, which would be cabin-luggage-sized and might be almost weather proof with a bit of sticky tape around the converter... It's just outside my budget for now, and obviously I have something to gain by improving my skills with my current equipment.

Chex: Thanks for the tip, but I do disable SR and use the in-lens stabilization. I would love to send it to you for QC testing, but it weighs about the same as a small lorry, so I couldn't possibly afford the postage...

A couple of you asked about the car engine: It was off. You are right about it being windy though, and the heron wasn't motionless either, and I've learned my lesson - 1/500s or above!

Monopod is usually not an option - too much gear to carry already, kids, spur-of-the-moment-shooting... but I have a steady hand (honestly) and use tree trunks, car windows etc as often as possible...

Again, thanks a bunch! I hope I replied to most of the questions - if I missed any I am sorry, but there have been so many useful replies, and I did read and appreciate them all!

Last edited by MetteHHH; 10-26-2011 at 04:52 AM. Reason: spelling errors :)
10-26-2011, 10:55 AM   #25
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That's a great shot MetteHHH! A complete turnaround, I think you found the lens' sweet spot. Looking forward to more
10-26-2011, 11:58 AM   #26
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one issue I have noticed is that many times at 500mm the DOF is quite small and especially when hand held, the focus indicator may not lock on the subject you think it has due to lens shake
10-26-2011, 01:09 PM   #27
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Well it sure looks like you have things sorted out! Nice shot!
10-27-2011, 05:02 PM   #28
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have Sigma check it out

I bought a 150-500 in January 2011. It too was a bit soft. I sent it to SigmaUSA to be checked. They found it had a forward focus problem that was not constant over the full range of the lens. They had Sigma Japan write new code for the lens (It is called rechipping but it is actually new firmware that is installed without opening the lens). The lens was remarkably improved when they returned it to me. The Sigma rep said at that time I had the only Pentax lens in North American that had been corrected with the new firmware. If your images are soft at 400mm, f/6.8, ISO 500 and you're sure your technique is okay, you should have the lens serviced. Mine produces reliably good images at that setting, hand held.
10-27-2011, 11:09 PM   #29
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Thanks oeriies, I might try that.

I did have my Sigma 28mm focus corrected a couple of years ago - but with that one it was an easy decision, focus was WAY off. The problem is, back then Sigma Denmark asked me to ship the house along with the lens for testing, and finding a couple of weeks where I would NOT miss my Sigma+k5 is... hard. At least it would have to wait for the end of fall migration!
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