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09-07-2009, 11:00 PM   #1
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About to Pull the Trigger on Sigma 120-400 but... [Double Post]

... not 100% sure...

Main use will be motorsport - motorbike racing

Perceived Advantages:

HSM = fast focus speed?
Reach - my other zoom lens is Sigma 70-200 f2.8
sharp at f8

No other alternative (in zoom lenses) at this focal length range. A prime doesn't give me the flexibility I need (can't zoom with your feet at the track as only have limited points approved for photography)

Perceived Disadvantages

soft at 400
weight - 1.64 kg
IQ compared to 70-200 f2.8

I have considered the Bigma (no HSM, slow), 150-500 (1 stop slower and no better IQ), 100-300 f4 (no HSM in Pentax mount). I have a monopod if it gets too heavy to handhold. I have no problem handholding the 70-200 at 1.32 kg.

I have read reviews, user reports, and sought advice here. Reports are a bit conflicting but later examples appear to be better than when the lens was initially released.

Having problems getting a copy to test, and there are no local dealers that will hire it, and no dealers offer a return policy just because I don't like it. I have contacted CR Kennedy (local importer/distributor) to see if they can arrange a test copy but have had no response to date.

What advice can you offer.

09-07-2009, 11:10 PM   #2
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DA* 300mm plus 1.4X TC ?

By all reports the 100-300 f4 Sigma is pretty good.

The only potential flaw in your logic is I think I have heard it said that HSM / SDM does not necessarily mean faster focus.

Hopefully someone with first hand xperience will chip in.
09-08-2009, 06:53 AM   #3
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I have both the Sigma 120-400 and the DA*300. The DA*300 is just a tack sharper as you may expect from a prime. If you are stuck on the location on the motor circuit and can't find the best sport for a DA*300 you may have to go with the Siggy. The AF is already pretty fast on my K10, but I expect it to be even faster on a K7.
I did post images shot with the Siggy and the DA* in this post, hope it helps in the decision
09-08-2009, 07:44 PM   #4
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Original Poster
Thank you both for posting

I have erroneously assumed that the Sigma screw drive lenses wopuld be slower than HSM. On this basis I had excluded the 100-300 f4. It seems not only is the focus speed as fast as the HSM lenses - it may well be faster and has the added benefit of maginifient IQ.

Andre - I see you are from Eindhoven. My wife's father's family are from there. Her grandfather, grandmother, father and uncles emigrated in the 50's to Perth.

09-09-2009, 03:55 AM   #5
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It's a small world nowadays.
09-09-2009, 12:44 PM   #6
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Really I think any of those lenses will do just fine. You will need the monopod unless you have something to lean on though, I find the big sigma zooms are very tiring to handhold for more than a few minutes at a time.

Here's a few from the bigma I have lying around. I expect I could get much better results if I got to try my hand at it more than once or twice a year :


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