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02-09-2011, 12:11 PM   #76
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QuoteOriginally posted by pxpaulx Quote
Bert,

I am sure quite a few of us have read that review - some of it reads as though the 120-400mm might in fact just be a pint glass shrouded in a lens casing, when that is not really the case. There are also some real-world user reviews out there that appear to provide useable results!

Also, when it comes to Sigma you definitely can't judge based on a single lens review - their QC can be pretty poor at times.
True!

JP

02-09-2011, 12:34 PM   #77
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Unfortunately as Pentax users we don't have any 1st party lenses to give this a good side-by-side with. I was pretty impressed with the 120-400mm based on this canon user's review (including side-by-sides with a 70-200mm F4, 300mm F4 and 100-400mm F4 at comparable focal lengths):

http://darwinwiggett.wordpress.com - lens-review-the-sigma-120-400-4-5-5-6
02-09-2011, 04:14 PM   #78
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After shooting today, admittedly in low light, I was able to get a great image at 120mm but the wires across the river, completely clear at 1:1 in the 120mm shot, were blurred in the 400 mm shot. What good is having a 400mm lens if I can get a clearer image by blowing up a 120? I have a Sigma 70-300, this lens was bought for the 300-400 range.. if it doesn't perform at that end, and my experience would suggest it doesn't, I won't carry it, because it's heavy. My Sigma 70-300 is barely noticeable in my camera pack. I'm starting to think a cropped image taken with a 60-250 would be sharper than the same image taken with this lens at 400. It's something worth investigating.

Anyway, unless tomorrow I can figure out a way to get decent results between 300 and 400mm, it's going back.

Last edited by normhead; 02-09-2011 at 04:38 PM.
02-09-2011, 11:04 PM   #79
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QuoteOriginally posted by normhead Quote
I'm starting to think a cropped image taken with a 60-250 would be sharper than the same image taken with this lens at 400. I
That's exactly my thinking with either the 60-250 or *300. They are virtually the same price here (US$1285) so if the quality is very similar I'd prefer the flexibility of the zoom however if there is a very clear IQ difference then I'd forego the flexibility for the IQ and just carry another lense.

02-10-2011, 03:34 AM   #80
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QuoteOriginally posted by normhead Quote
Anyway, unless tomorrow I can figure out a way to get decent results between 300 and 400mm, it's going back.
The weak spot is between 300 and 400mm, and worse at longer end.
Does it produde as good as the 70-300 @300mm ?

400mm is not as good, but I m hardly use this range. I found 400mm is 'usable' if I don't have a choice, rather @300-320mm and crop. I have both versions of this lens in K mount and use the OS version more and more, but not at 400mm. I ll keep the OS version. As for the moment, it's still the cheapest in this range to cover my need of portraits.
02-10-2011, 06:58 AM - 1 Like   #81
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QuoteOriginally posted by pxpaulx Quote
Bert,

I am sure quite a few of us have read that review - some of it reads as though the 120-400mm might in fact just be a pint glass shrouded in a lens casing, when that is not really the case. There are also some real-world user reviews out there that appear to provide useable results!

Also, when it comes to Sigma you definitely can't judge based on a single lens review - their QC can be pretty poor at times.
Hi Paul, you are right. There are good user reviews available for this lens.
However, one should not underestimate the effect that people will write a review in justification of their own choices.
What I'm trying to say is that people are more likely to write a positive review on equipment they just spend a lot of money on, than an objective review.

That is also true for me.
I.e. I did buy a K-7 as an upgrade to my K10D and afterwards I was not pleased at all with the character of its high ISO noise.
It took me a long time to admit to myself that I should not have spend that kind of money on that camera.
The K-5 is what the K-7 should have been.

Back to the discussion:
As an engineer I like to trust proper measurements over opinions.
The DA*300 is superior over the 120-400mm, with proper AF fine tuning achieving better results is not a problem.
True, it is not a zoom, than a 200mm / 300mm combo or the 60-250mm with cropping is IMHO a better option.
I've made wildlife picture in Tanzania with a 18-250mm zoom, not bad at 250mm. And I was very pleased with the results then.
But when compared with the 60-250mm results they look not good at all!
Our minds is playing tricks with us...

I'm not saying you cannot get good results with the Sigma (look at the graph: 400mm at f8 - f11 is Ok), however I'd like to be able to use a lens like that at low light as well.

The day Sigma, Tamron, Pentax or any body else would make a >= 400mm zoom with the sharpness of a DA* lens, I'll sell my 60-250 and I will buy it.

- Bert
02-10-2011, 07:11 AM   #82
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QuoteOriginally posted by bymy141 Quote
However, one should not underestimate the effect that people will write a review in justification of their own choices.
Totally agree.
I have my needs. This lens is the cheapest mean and most convenience. Sure I'll go for the DA*200/300 combo if I have more money. Also the focal range had been covered by the 50-135, so these extra ends mm are not totally required. I also selected the K20 instead of K7. I don't think a zoom in this range can be good or cheap, and I keep the lens if circumstances allow. Seems that I have to sell one of these, no point to own two...
02-10-2011, 07:27 AM   #83
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Sigmas quality control has been a bit iffy for a while now, some people seem to get really good lenses and others get old dogs.

Just keep sending it back until you get a good one .. (as long as you are not paying the return postage costs).

My 50-500mm is still one of the best lenses I have and its a few years old now .. I could take the same shot with my 60-250mm and crop but it wouldn't be any better imo.

02-10-2011, 09:11 AM   #84
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My experience with the 120-400

I was concerned over quality control issues, but I got a good one. There was no noticeable decentering, focus was sharp and consistent and the HSM focusing was fast and quiet. Build quality was very good.

Optically, it was very good from 120 to 300mm and softened in the range to 400mm, but still wasn't bad, especially when stopped down. As another poster already noted, you need to also consider your normal lighting conditions and outdoors here in Arizona you don't need to use a telephoto wide open.

I sold it on, because I found the range wasn't quite what I was using (I'm replacing it with a 70-200).

I suspect that the optical quality of the new OS version is about the same as the previous one I owned - very good, especially at wider zoom settings, but a tad soft at the long end.

Mike
02-10-2011, 11:50 AM   #85
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So just as an update, I shot over 100 images this morning, and I've arranged to take the lens back. The only thing I need from a lens right now is good sharp images at 400mm. This lens doesn't do that. Since I plan to be shooting wildlife, I need sharp at a distance. This morning I took at least 50 images, at about 120 feet. I used a tripod, a shutter delay, had the OS turned on from time to time, I just can't get a sharp image at distance with this lens, which is all I would be buying it for. At closer distances, as in for the birds on my porch, it's a great lens. Still not as sharp as it could be but adequate.

So, long story short, it's going back, and I'm ordering the Pentax Da 60-250. Currently I have an older Sigma 70-300 which is similar quality in the shorter lengths to the 120-400, just a third the price and 1/3 the weight.

On the other hand, if you are birder and you can get close to your subjects, you might like this lens. Tell me how you could get a shot like this without it? It's the first thing I'll try with the new lens.



My dog from 100 feet, just not sharp enough.


Last edited by normhead; 02-10-2011 at 12:02 PM.
02-10-2011, 12:24 PM   #86
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QuoteOriginally posted by normhead Quote
...The only thing I need from a lens right now is good sharp images at 400mm....
So, long story short, it's going back, and I'm ordering the Pentax Da 60-250....
Hi,

Perhaps you should look into the DA*300. Even sharper and longer than the DA*60-250mm.
That lens with a Pentax 1.7 TC will give better results than the once you are showing.
Here is a 60-250mm + Pentax 1.7 AF TC, hand held from a boat at its long end:



Good luck, Bert
02-10-2011, 12:48 PM   #87
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Thanks for posting all these shots Norm. I'm looking forward to seeing what you get out of the 60-250 as I'd like the flexibility of the zoom .... but I think the *300 IQ is calling me.

Nice shot Bert !
02-10-2011, 01:09 PM   #88
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QuoteOriginally posted by normhead Quote
My dog from 100 feet, just not sharp enough.
That's just plain nasty.

Sigma 50-500mm handheld at 500mm








02-10-2011, 02:55 PM   #89
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Thanks for those shots.
DLSR gear tests the 60-25- here. and I don't think you could get a more positive review.

QuoteQuote:
Conclusion
Optically, the Pentax 60-250mm ƒ/4 is a winner: with excellent results for sharpness, even wide open, low amounts of CA and virtually no light falloff or distortion, it's an easy decision if you're already considering this lens and just needed to know whether or not it performed.
I'd consider the 300 as my next purchase, it has a great rating in the lens review section... but, I'm shooting with a Sigma 70-300 macro above 135 mm. That whole range needs to be addressed for me personally. And then weight becomes an issue. My theory has always been slow zooms, fast primes. I'm not sure where that leaves me with Pentax right now, but for me, a zoom to walk around with is a must. A prime is something to pull out of my bag if I have time. Even with this lens, the 18-135 will still be on my camera most of the time, with this lens on the second body when I think I might need it, and the Tamron 90 2.8 and 50 1.8 for lower light. It doesn't cover everything, but it's still a pretty light camera bag and I still believe, it's better to be close. This will force the issue.
02-11-2011, 12:04 PM   #90
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Yep. Even the Tamron 500 Mirror can get sharper shots than Norm's dog at 100ft (30M).

this one at about 25M :



and this one at roughly 15M :

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