Fast focus for baby shots
Posted 14/04/2012 - 11:19
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whelmed wrote:
Can I conclude then that there is nothing that will be faster than my 35mm f2.4 then?
A 126 Instamatic? It's fixed focus so no focus speed issues at all. Can I conclude then that there is nothing that will be faster than my 35mm f2.4 then?
John
John K
Posted 14/04/2012 - 13:54
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JAK wrote:
It still is true that SDM is nothing to do with IQ as said in the original post.
John
Actually that is not strictly true either.It still is true that SDM is nothing to do with IQ as said in the original post.
John
As Pentax only make their "professional range" with SDM and considering the price of them you would be quite within your rights to expect better IQ than a lens without.
There are of course lenses still made that have IQ just as good (or even better) such as the 31mm/49mm/77mm but they are old school and are unlikely to be reworked for SDM.
Posted 14/04/2012 - 17:29
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Mike-P wrote:
As Pentax only make their "professional range" with SDM and considering the price of them you would be quite within your rights to expect better IQ than a lens without.
There are of course lenses still made that have IQ just as good (or even better) such as the 31mm/49mm/77mm but they are old school and are unlikely to be reworked for SDM.
Don't wish to appear rude, but how on earth can a lens focussing system have any relation to a lens's optics?JAK wrote:
It still is true that SDM is nothing to do with IQ as said in the original post.
John
Actually that is not strictly true either.It still is true that SDM is nothing to do with IQ as said in the original post.
John
As Pentax only make their "professional range" with SDM and considering the price of them you would be quite within your rights to expect better IQ than a lens without.
There are of course lenses still made that have IQ just as good (or even better) such as the 31mm/49mm/77mm but they are old school and are unlikely to be reworked for SDM.
Saying 'price' is not really a valid answer!
As an aside, I'm not convinced that this thread was ever meant to be taken seriously!
John
John K
Posted 14/04/2012 - 17:57
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JAK wrote:
Don't wish to appear rude, but how on earth can a lens focussing system have any relation to a lens's optics?
Easily.Don't wish to appear rude, but how on earth can a lens focussing system have any relation to a lens's optics?
If the relationship is one of correlation, rather than causation.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Posted 14/04/2012 - 18:02
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It's pretty simple I would say
Pentax uses its "premium" SDM focusing motor for it's premium lenses which are supposedly the best they produce (given their price)
Since they are the best lenses Pentax make is it not safe to say that the optics are therefore included in that premium upgrade or do you think the extra cost goes purely on a motor that probably costs a few pounds at best?. It is generally accepted that the lenses with SDM have the best optics (16-50mm vs 16-45mm, 55mm vs 50mm, 50-135mm vs 50-200mm, 60-250mm vs 55-300mm).
I would say that was a totally valid answer, no matter how many times you try and justify your statement (which I believe at the start was saying SDM was for their fastest focusing lenses?).
Pentax uses its "premium" SDM focusing motor for it's premium lenses which are supposedly the best they produce (given their price)
Since they are the best lenses Pentax make is it not safe to say that the optics are therefore included in that premium upgrade or do you think the extra cost goes purely on a motor that probably costs a few pounds at best?. It is generally accepted that the lenses with SDM have the best optics (16-50mm vs 16-45mm, 55mm vs 50mm, 50-135mm vs 50-200mm, 60-250mm vs 55-300mm).
I would say that was a totally valid answer, no matter how many times you try and justify your statement (which I believe at the start was saying SDM was for their fastest focusing lenses?).
Posted 14/04/2012 - 18:04
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17-70 ?
Already apologised for that - I had misunderstood the meaning of supersonic as used by Pentax. Thought it related to supersonic as in fast aircraft, not quietness!
John
Quote:
would say that was a totally valid answer, no matter how many times you try and justify your statement (which I believe at the start was saying SDM was for their fastest focusing lenses?).
would say that was a totally valid answer, no matter how many times you try and justify your statement (which I believe at the start was saying SDM was for their fastest focusing lenses?).
Already apologised for that - I had misunderstood the meaning of supersonic as used by Pentax. Thought it related to supersonic as in fast aircraft, not quietness!
Quote:
It is generally accepted that the lenses with SDM have the best optics (16-50mm...
Some apparently reject the lens because it is SDM, so I have read here.It is generally accepted that the lenses with SDM have the best optics (16-50mm...
John
John K
Posted 14/04/2012 - 18:09
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17-70mm is better than both the 16-45mm and the 18-55mm kit lens, I believe it was bought out as an upgrade for the kit lens (having better optics) and to replace the 16-45mm which was already getting on a bit when SDM was first bought out. The 16-50mm is another level up because of it's faster aperture.
Anyway that's just my take on it, I may be totally wrong.
Anyway that's just my take on it, I may be totally wrong.
Posted 14/04/2012 - 18:19
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Optically the 17-70 (to me) is not quite as good as the the 16-45 but is a more convenient lens. It's certainly fast and quiet focussing, but not a pro lens.
If you read Photozone's review of it link it states
John
If you read Photozone's review of it link it states
Quote:
The fast and near-silent ultrasonic AF is also a very welcome new feature.
which is where I got the impression that SDM was supposed to be faster and why I purchased one.The fast and near-silent ultrasonic AF is also a very welcome new feature.
John
John K
Posted 14/04/2012 - 18:21
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JAK wrote:
17-70 ?
...
Some apparently reject the lens because it is SDM, so I have read here.
Not because of its optics.
17-70 ?
...
Some apparently reject the lens because it is SDM, so I have read here.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Posted 14/04/2012 - 18:23
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No, because of SDM failures. What I think happens though is that the SDM motors get over torqued if the lens is quick shifted.
John
John
John K
Posted 14/04/2012 - 19:16
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Its not a pro lens and the only SDM lens that isn't (Taken by the *16-50mm) but its an upgrade to a current lens (the 18-55mm) costs more and also has better optics.
If you discount the 16-45mm (I disagree that it is optically better than the 17-70mm but that's another discussion) as it's no longer made is it not safe to say then that all SDM lenses are more expensive than the lens they are competing with and also have better IQ. ?
If you discount the 16-45mm (I disagree that it is optically better than the 17-70mm but that's another discussion) as it's no longer made is it not safe to say then that all SDM lenses are more expensive than the lens they are competing with and also have better IQ. ?
Posted 14/04/2012 - 19:51
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Install 3 or 4 100 watt CFL bulbs.
You'll have much more light, which will speed up focusing and enable you to use a smaller aperture, thus gaining DOF.
G
You'll have much more light, which will speed up focusing and enable you to use a smaller aperture, thus gaining DOF.
G
Keywords: Charming, polite, and generally agreeable.
Posted 14/04/2012 - 20:00
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George Lazarette wrote:
Install 3 or 4 100 watt CFL bulbs.
You'll have much more light, which will speed up focusing and enable you to use a smaller aperture, thus gaining DOF.
G
And freaking the hell out of the poor baby !
Install 3 or 4 100 watt CFL bulbs.
You'll have much more light, which will speed up focusing and enable you to use a smaller aperture, thus gaining DOF.
G
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