Pentax D FA 24-70mm questions


cardiffgareth

Link Posted 13/09/2019 - 16:34
This has probably been asked to death already but ...!

I've just reserved the Pentax D FA 24-70mm in Wex Photo pending a reply on their part ex prices. I have the D FA 28-105mm WR and also the Sigma EX DG 24-70mm but wanted to combine the two lenses so I have a wide standard zoom that is WR and means with my current lens, I'm not limited to being a fair weather shooter. They may give me some shocking part ex prices and it's a no go but in case the sums and the planets all line up right I wanted to know a few things.

Firstly, for those who have own the Sigma 24-70mm as well as the Pentax 24-70mm, will I see much of a noticeable difference in image quality as the Sigma is no slouch at the mo.

Secondly, the Sigma on the K1 nails focus every time, even at f2.8 so doesn't front or back focus. Does the Pentax suffer from this or will that nail AF dead on also? I know some will say how do you know but I do pixel peep to check and for portraits it's a must.

Lastly, its a SDM lens so will this start to suffer from the issues that dogged the 16-50mm and 50-135mm and have motor failure? The Sigma uses good old screw drive so it's never a worry for me at the mo!

Thanks

Gareth
Gareth
Welsh Photographer

My outfit: K1 gripped - Pentax DFA 28-105mm - Sigma 70-200mm HSM Macro - Sigma 105mm - Pentax FA 35mm f2 - Tokina 20-35mm, Sigma 50-500mm - Pentax AF 540 FGZ Ii

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Mike-P

Link Posted 13/09/2019 - 16:53
I had the final version of the Sigma (HSM not screwdrive) and it was a great lens but I found a Pentax version at a very good price so bought it. Having had previous versions of the Sigma I found the final one to be the best of the bunch, HSM is faster and quieter than screw drive and it was definately sharper in the corners.

I have to say the Pentax is sharper again but not oustandingly so (remember I am comparing it to the HSM lens which is sharper than the screw drive) and I struggled as to whether I should sell it on but in the end I kept the Pentax lens for the WR the fact I have always found Sigma's HSM to be a little dodgy where focus accuracy is concerned ... 90 times out of 100 it will nail it but Pentax lenses seem to get it right every time.

As for SDM it's a different motor so no worries there. (obviously I will not guarantee that answer)
No equipment list here but thanks for taking an interest. My Flickr

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cardiffgareth

Link Posted 13/09/2019 - 17:11
Thanks Mike, their offer wasn't too shabby so gonna do the dead so to speak.

Interestingly I offered the Irix 15mm in the part ex quote also but they said they don't take them in?!
Gareth
Welsh Photographer

My outfit: K1 gripped - Pentax DFA 28-105mm - Sigma 70-200mm HSM Macro - Sigma 105mm - Pentax FA 35mm f2 - Tokina 20-35mm, Sigma 50-500mm - Pentax AF 540 FGZ Ii

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My 500px

pschlute

Link Posted 13/09/2019 - 17:18
The 24-70 is a great lens. Focussing is quick; silent; and accurate.

As Mike said, the motor is completely different.

Make use of the AF/FA menu to check that focussing is spot on.
Peter



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ronniemac

Link Posted 13/09/2019 - 17:40
Did you consider combining the 15-30 with the 28-105?

Although the latter is not as fast as the Pentax 24-70, the 28-105 is reportedly sharper than 24-70. This would give you a WR combination covering 15-105 even if it is a little more expensive. For landscape shooting it's quite a good combination. except that the 15-30 requires a more complex filter arrangement.

Good luck with whatever you settle for.

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cardiffgareth

Link Posted 13/09/2019 - 17:48
Thanks both

I do like the 15-30mm but after investing heavily in 100mm filters then it's a no go for me.

Interesting about that sharpness comment, that's thrown a curve ball of thought about the 2 lenses and what to do!

Best do a quick online comparison of the 2 lenses and sharpness before shipping my lenses off to them
Gareth
Welsh Photographer

My outfit: K1 gripped - Pentax DFA 28-105mm - Sigma 70-200mm HSM Macro - Sigma 105mm - Pentax FA 35mm f2 - Tokina 20-35mm, Sigma 50-500mm - Pentax AF 540 FGZ Ii

My Flickr

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RobL

Link Posted 13/09/2019 - 18:21
cardiffgareth wrote:
Thanks both

I do like the 15-30mm but after investing heavily in 100mm filters then it's a no go for me.

Interesting about that sharpness comment, that's thrown a curve ball of thought about the 2 lenses and what to do!

Best do a quick online comparison of the 2 lenses and sharpness before shipping my lenses off to them

I'm not convinced that the 28-105 is sharper, it's a good all-rounder but the 24-70 is what I take when I want to get the best, and of course it is f2.8 all the way up. As for filters I bought the Lee Filters SW150 after getting the 15-30 but have come to realise it is rather limiting; the collar, mount and large filters take a lot of room and the adapters for other lenses have quite bulky sleeves which partly cover the lens barrel so you wouldn't want more than one or two whereas the SW100 system looks much more manageable, and I am wondering if I should have opted for that instead as it would unrealistic to buy and carry both systems.

Here is a thought - how about a couple of primes instead of swopping your 28-105? I have taken to carrying these now for lightness and much sharper results and I have been surprised at how little the fixed focal length has been a problem.
Last Edited by RobL on 13/09/2019 - 18:21

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