Sigma IQ Expectations...

Thanks, David.

1/180th.(flash) @ f8, handheld.

No other camera settings changed.

Roger.

Hi Roger
Looking at your recent gallery uploads it looks as if as in my camera if f8 can be achieved its the best aperture for the Bigma. It may have to be at the expense of ISO or worst shutter speed but f8 works for me providing the lights good enough.
For the last few weeks as light has got better I have used either
1) In medium/poor light PAv with aperature at f8 if possible, shutter 1/200sec or better if possible, ISO set to max of between 800>1250 if it does go this high noise can be a problem.
2) If the light gets very good use Tv or Av if you want to keep f8, manual ISO as low as you can afford to go for the situation, this depends on what shutter speed you can get away with or require.

From your recent uploads and the settings I would presume light was in short supply so they are very good considering.
The https://www.pentaxuser.com/photo/mallard--droplets-46584/large is excellent and shows what the camera and lens can do despite the large aperture.
I liked the rug bug https://www.pentaxuser.com/photo/grub----46717/large excellent.
Regards David

Hi David .... the 150-500 is not the Bigma (that is the 50-500) it is called the Bigmos.

Coker - I'm not sure testing with a flash is the right way to prove anything. IMHO this lens should be much sharper than you have been displaying, outside and in real world decent lighting - not with a flash. Good luck with finding a solution. If you bought it from SRS why not contact Chris ? Maybe he can other a solution or offer advice.

[quote:3496ace15f="Frogfish"]Hi David .... the 150-500 is not the Bigma (that is the 50-500) it is called the Bigmos.

I stand corrected, my lens is the 150-500OS. Sorry for any confusion.
Regards David

Out this afternoon in pretty good light.
K7, 150-500(again!)
ISO 800, 1/800th. @f8.
Full frame jpeg straight from camera.
(Crop is on The Gallery).



[IMG]http://i1021.photobucket.com/albums/af340/rogerhlane/Swallows102.jpg[/IMG]

Spoke to SRS today. Advised to speak, initially, to Sigma for any hints/tips/advice they may have, then, if necessary, get back to SRS.


The IQ, self-evidently, is not good(!) & not just because of K7+iso800.

I shall endure!

Roger.

Did you use a solid tripod for this shot? To test sharpness of a lens, it's probably best to tripod mount and shoot a subject with plenty of detail in one plane. So, a brick wall is always a basic stand by subject. This will also show any distortion. For more detail, a newspaper pinned up on the wall will definitely show how much resolution you are getting.

Hi Roger
From the settings you used you should have a much better image than the one you have. I would not expect to have to use a tripod for this. In fact I have never used a tripod with my Sigma 150-500 and have achieved far better results at shutter speed as low as 1/200 providing the SR is swiched on, with apertures wider than f8 if lights poor. I have read that there are some bad Sigma 150-500 lenses out there so get on to SRS and try to get it swappped, after all I think you have tried every thing else.
Kind regards and best of luck David

Thanks, David.
I'm ringing Chris at SRS tomorrow!

(Just been looking at your portfolio of birdie shots with the K7/150-500.........

encouraging & inspiring!).

Roger.

Hi Roger
Thanks very much for the complement it makes it all so much more enjoyable.
I know I bang on about it but almost all my shots for the last year are taken in RAW, are you using RAW?
I use RAW no matter what lens is fitted, my images are less than crisp with jpeg. I dont think mine would be anywhere near as good if I used jpeg.
With RAW the photos are often sharp enough, however you have the option to sharpen the way you want if as required. Playing with the exposure, black and clarity levels etc can also transform an iffy image into a pretty good one.
Regards David

I might have missed something in the thread... but in the garden bench images you said jpeg from camera compared to sharpened jpeg - does this not imply that the problem lies with the default jpeg sharpening setting within the camera?

If you can sharpen the jpeg to produce the image you want I would have thought, in my unknowledgeable way, that the image info has been correctly captured by the lens.

I would agree with David's above comment that you should experiment with shooting raw?

Thanks, David & Martyn for the suggestions re RAW.

The few times I've tried RAW+ with other lenses on the K7, then allowed it to convert to a jpeg on auto., I've not seen any difference between that & the jpeg straight from the camera, of exactly the same shot.
I take on board the ability to recover an image that, for whatever reason, has had to be taken under less than ideal conditions. From what you, & many others, have said RAW is a very powerful tool in that respect.
However.....
in the case of my 150-500, I don't think I should have to treat every shot as being "unrecoverable" & thus be obliged to use RAW.
All my other lenses allow the camera to produce images that are more than acceptable, with a touch or two in PSE9.
If I had obtained a really cheap "milk-bottle-bottom" lens, of dubious marque, for 25 quid, I'd be happy to slave over a hot RAW, just to prove a point, perhaps. But...

We'll see what Chris comes up with later on today.....


Thanks again,

Roger.

Hi Roger, have you tried this? If focus adjustmrent isn't off, then I think it needs to go back.

Hi, Alan.

If you look at the Linnet image in The Gallery, I think you'll see that there isn't anything in front of or behind the bird that is in any better focus than the subject itself!
I have checked on other images & the same applies.

I'm in contact with Chris at SRS, even as we speak.

Roger.

We wait with our fingers crossed, good luck
Regards David

It's on its way back to Watford!

R.