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09-02-2009, 04:21 AM   #1
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ultimate lens test

the troll is back

ok here goes
da* lens V sigma
2 k200d cameras
both cameras at same setting pics taken at same time
twice as many sigma pic were in focus compared with the pentax da*50 -135
the sigma lens pics were much brighter than the pentax lens

pentax aus supplied me with 2 test lenses to try and sort out problem with focussing problem

this shouldnt be da* lenses are supposed to be designed for pentax cameras

in overcast conditions the pentax lenses cant focus properly

bright sunlight no problems with pentax leses

pentax aus are prepared to exchange the 2 da* lenses I have for sigma lenses

for those of you who had a go at me before these are the facts

if I was a troll as many suggested then pentax aus have beeen taken for a ride

so it can not be user error as some suggested 2 cameras 2 lenses

09-02-2009, 05:18 AM   #2
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before I post my no trolling allowed sign I have a question.

did you ever, during the test, switch bodies between pentax and sigma lenses?

Just to make sure you were not blaiming the lens when in fact it is a body issue.
09-02-2009, 05:19 AM   #3
Ash
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Why even post this?
Ultimate lens test? I think not.

Rarely have I heard a bad report about the 50-135 on this forum with hundreds of users, many of them pro, and here you are with 2 copies of these lenses with no pics to back it up, no evidence that there isn't user error (even given your previous photographic experience) claiming they focus poorly and produce dull images, and then say 'these are the facts'.

Well, they can be your facts - good for you.
Thanks for sharing, now move right along and enjoy your Sigma lenses...
09-02-2009, 05:32 AM   #4
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Original Poster
QuoteOriginally posted by Lowell Goudge Quote
before I post my no trolling allowed sign I have a question.

did you ever, during the test, switch bodies between pentax and sigma lenses?

Just to make sure you were not blaiming the lens when in fact it is a body issue.
I had 2 separate bodies both new k200

1 with sigma lens and 1 with pentax lens

I could swap bodies over and test again but the light was fading so i just did what i could in the time

I will have another go 2morrow

well its a combination of body and lens I think the k7 with focus adjustment might work
pentax aus will lend me a k7 to try as well but they are out of stock

09-02-2009, 05:43 AM   #5
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QuoteOriginally posted by Ash Quote
Why even post this?
Ultimate lens test? I think not.

Rarely have I heard a bad report about the 50-135 on this forum with hundreds of users, many of them pro, and here you are with 2 copies of these lenses with no pics to back it up, no evidence that there isn't user error (even given your previous photographic experience) claiming they focus poorly and produce dull images, and then say 'these are the facts'.

Well, they can be your facts - good for you.
Thanks for sharing, now move right along and enjoy your Sigma lenses...
yep I understand your view and I think that most user would have k7 and this might then not be a problem

there may be hundreds of users out there but for the work I am doing there is a problem

pentax aus have recognised this otherwise they would not be lending me cameras and lenses to try and fix the problem

as I said in my previous post in sunlight there is no problem only in overcast conditions

the store owner pentax rep and pentax aus have seen a sample load of pics
thats why they are lending me equipment to try and sort it out

they have lent me $1000s worth of gear so I would say its a real issue sorry if it offends you but they trust me enough to do this

I would say thats not bad for them to do this
09-02-2009, 05:43 AM   #6
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in re-reading the post, it is interesting that you state the pentax can't focus on cloudy days.,

since focus is a function of contrast, can you show exactly what your target is?
09-02-2009, 05:50 AM   #7
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QuoteOriginally posted by ranters Quote
pentax aus have recognised this otherwise they would not be lending me cameras and lenses to try and fix the problem

they have lent me $1000s worth of gear so I would say its a real issue sorry if it offends you but they trust me enough to do this

I would say thats not bad for them to do this
All well and good - but did I sound offended to you?
Hardly the case.

You're sounding like somewhat of an authority in Pentax gear for 'them' (whoever they are) to be giving you the responsibility of 'fixing' their faulty equipment.

The hundreds of others here with the same 'faulty' equipment have been producing absolutely stellar photos - plenty of evidence of that here...

The way you're presenting yourself here, though, hasn't shown that you've methodically or systematically tested any of the equipment in a scientific or controlled manner. This hampers credibility considerably...
09-02-2009, 06:03 AM   #8
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If you are really testing equipment you should be using a studio to do so. In the studio you can mimic all kinds of lighting you will find in the natural world ( and some lighting you will never, ever see in the natural world) and you will be able to light things and produce results in a repeatable fashion, That is what proper scientific methodical testing is. And only until you do that will anyone take you seriously. I test my lenses under studio lights, because then I can make Direct comparisons between them...I can compare the results from a Pentax FA* 80-200mm f/2.8 bought in 1995 against a canon 70-200mm f/2.8L IS bought in 2007. Even two wireless AF540FGZ flash units triggered wireless can be used in situ of professional studio lighting. but of course such tests have to be done indoors under Controlled conditions. - not haphazard fooling around in available light outdoors.

excuse my scepticism, but I get the strong impression that you aren't very good at problem solving.


Last edited by Digitalis; 09-02-2009 at 06:16 AM.
09-02-2009, 08:15 AM   #9
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>pentax aus have recognised this otherwise they would not be lending me cameras and lenses to try and fix the problem<

I would respectfully point out that if Pentax thought there was a *real* problem, they would be doing the investigation themselves under controlled conditions; they wouldn't be leaving the investigation in the hands of some guy with two k200d bodies.

If they have loaned you equipment, it's because Pentax values customer support and will do many things to try and make customers happy.
09-02-2009, 08:29 AM   #10
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QuoteOriginally posted by ranters Quote
yep I understand your view and I think that most user would have k7 and this might then not be a problem

I am not going to question the testing but I will question this statement above....

The K20 and K7 focus adjust is helpful for fixed length prime lenses. But with zooms, too often you need one adjustment at the wide end and another at the long end, and the K7 and K20 can not do that type of adjustment. One setting adjust per lens.

So dont count on the Lens focus adjust feature of the K7 to solve the problem.
09-02-2009, 03:38 PM   #11
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QuoteOriginally posted by ranters Quote
if I was a troll as many suggested then pentax aus have beeen taken for a ride
Without seeing the results of your test, or knowing how you conducted it, it's impossible to say if you've corrected the very obvious errors in your previous test or not.
09-02-2009, 03:46 PM   #12
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Well, as the old saying goes... Without pics, this thread is useless.

Regards,
Mike
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