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05-29-2007, 01:26 PM   #16
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Pentax should just continue making the FA* 300mm/2.8- the AF is lightning fast (as always ) even without SDM. It won't happen because of their switch over to plastic 'polycarbonate' barrels, though

QuoteOriginally posted by CSPronken:
The planned 35mm is a DA and should have SDM. What reason would Pentax have to only equip the DA* lenses with SDM? An entry level Nikon D40 doesn't even AF without in lens motors, so why restrict it to up market DA* lenses?
You're right- I completely forgot about the 35mm.

The SDM probably won't improve AF much on Pentax lenses, however, if at all, since the way AF works on Canon and Nikon has always been different from that of Pentax. All Canon lenses have built-in AF motors (am I right?) whereas no Pentax lenses currently do. I can only praise the AF speed on my 300mm, and it doesn't have SDM, does it?



I guess it all depends on the gearing of the AF mechanism within each individual lens. Some lenses take forever to focus (like the macros), while others (like the FA 35mm/2 and 300mm above) just couldn't be better. Macro lenses would probably benefit the most from SDM, IMO, yet none are currently projected by Pentax...

That's why I'm sticking to the FA version.

[/endrant]


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05-29-2007, 05:07 PM   #17
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QuoteOriginally posted by Mo Quote
Pentax should just continue making the FA* 300mm/2.8- the AF is lightning fast (as always ) even without SDM. It won't happen because of their switch over to plastic 'polycarbonate' barrels, though

The SDM probably won't improve AF much on Pentax lenses, however, if at all, since the way AF works on Canon and Nikon has always been different from that of Pentax. All Canon lenses have built-in AF motors (am I right?) whereas no Pentax lenses currently do. I can only praise the AF speed on my 300mm, and it doesn't have SDM, does it?

I guess it all depends on the gearing of the AF mechanism within each individual lens. Some lenses take forever to focus (like the macros), while others (like the FA 35mm/2 and 300mm above) just couldn't be better. Macro lenses would probably benefit the most from SDM, IMO, yet none are currently projected by Pentax...

That's why I'm sticking to the FA version.

[/endrant]
Pentax does make new DA lenses with metal bodies, including the DA 14mm and the three DA limited lenses. So there is some capability in Vietnam to make metal bodied lenses.

Canon uses in-lens motors for AF with all of the EOS mount lenses. They also use an electrical contact to trigger the aperture in the lens (using an electro-magnetic mechanism, I believe). So all of the lens mechanism actuation is through electrical rather than mechanical linkage. The AF sensor is still in the camera body, though. Nikon is pretty much the same as the Pentax K10D: mechanical linkage for the aperture, and both mechanical and electrical connections available for the auto-focus. Again, the AF sensor is in the body. So Nikon and Pentax pretty much work the same in terms of the lens connections, whereas Canon has eliminated the mechanical coupling for the automatic aperture (which allows even tilt/shift lenses to have an automatic aperture). I doubt if the aperture mechanism really makes much difference in terms of performance and reliability, but the electrical AF system is a different story.

SDM certainly has the potential to improve AF response, since the lens motor performance can be balanced for the specific lens in use and mounted directly into the lens barrel where the focusing elements need to move. This reduces the drag and mass of the focusing mechanism and eliminates the play in the body/lens connection. The result should be improved response time and decreased noise. If you've ever used a long telephoto Canon EOS lens in AF mode, the difference is obvious. It won't help in situations where the sensor can't lock due to low light or lack of contrast, but it should be better for fast action shots. Whether ther Pentax SDM lives up to the potential remains to be seen.
05-29-2007, 06:14 PM   #18
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QuoteOriginally posted by GaryML Quote
Pentax does make new DA lenses with metal bodies, including the DA 14mm and the three DA limited lenses. So there is some capability in Vietnam to make metal bodied lenses.

SDM certainly has the potential to improve AF response, since the lens motor performance can be balanced for the specific lens in use and mounted directly into the lens barrel where the focusing elements need to move. This reduces the drag and mass of the focusing mechanism and eliminates the play in the body/lens connection. The result should be improved response time and decreased noise. If you've ever used a long telephoto Canon EOS lens in AF mode, the difference is obvious. It won't help in situations where the sensor can't lock due to low light or lack of contrast, but it should be better for fast action shots. Whether ther Pentax SDM lives up to the potential remains to be seen.
The limited's are indeed very well-built, but since their barrels are small compared to most other lenses, I doubt that the standard factory wouldn't be able to produce them. It's the big guns that they'll have trouble with...

You have a good point: we have yet to see the SDM in action. Performance will definitely vary by lens, however, so I hope Pentax notices that and adds SDM to the slow-focusing lenses.

It would also be nice if Pentax were to combine power zoom and SDM in zoom lenses- after all, both systems use the same electrical contacts

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05-30-2007, 08:51 PM   #19
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Two lenses ...one a long fast zoom, either a 135-400 f/4 or even a 200-400 f/4. The other would be a 60-120 true macro lens, much like the Nikon 70-180 macro.

..Mike.

05-30-2007, 10:37 PM   #20
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- 150mm f2.8 Macro
- 17mm f2.8
06-05-2007, 01:22 PM   #21
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I'd like to see in the slightly faster but still compact f/4 or f/3.5-4.5, all with 8 aperture blades, IF, SDM, and quick-shift focus if possible.

More compact and reasonably-priced ultra-wides:
DA16 (OK, not a zoom, but DA* or DA limited)
DA14-28, especially if it can be made more compact than 12-24.

Upgraded moderate tele zoom - like 50-135 but not as big or expensive, better performing than 50-200 in overlapping range.
DA 40-120 (or 135) f/3.5-4

OK, these are perhaps a little redundant, but I love my 24-90 but wish it was just a *bit* wider.
DA 16-70 f/4 or f/3.5-4.5
DA 20-80 f/4 or f/3.5-4.5

Of course, I'd like to see some longer glass offered, but I'll let the people who really care request that.
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