Opinion needed on 55-300mm

photogerald · 07-15-2010, 06:48 PM

Originally posted by Laurentiu Cristofor

Strange - the note and the second list you provided seem to contradict each other. In the list, if I am reading it right, there are several HSM lenses that are marked as working on Pentax. It's true that the 70-200 MACRO HSM is marked as not working, but other HSM lenses are shown to keep AF with the teleconverters.

Looks like their guidance is a mess anyway.

That list is indeed confusing to read, now that you mention it. I believe the ones listed as "EX DG / HSM" in the table only had HSM in other mounts besides Pentax. For example, the "APO 100-300mm F4 EX DG / HSM".

I have the 1.4x matched converter and there's no way it would work with HSM/SDM as it lacks the PZ contacts.

newarts · 07-16-2010, 04:58 AM

Originally posted by Pentaxor

I think it would just be a matter of time where slow lenses would be as capable as fast lenses in such demanding situations.....

Not trying to pick a fight here, but I think we are not all that far away from theoretical limits. Last time I looked, sensors were about a factor of three below theoretical quantum efficiency limits - I think that included the Bayer filter strategy.

At the quantum efficiency limit, only software tricks can further improve S/N ratios (like an algorithm that decides "this area is sky & the sky has no noise"..etc..)

I suspect it may not be long before the remaining 2 stops sensitivity are picked up by sensor and software design, but there are practical limits not far away.

Dave

yoshizuki · 07-16-2010, 02:34 PM

the 55-300 is probably the best value for the money. It can have slow focus, but anything better, like the sigma 2.8s, come with a significant higher price and weight.
I have the DAL version and bought a cheap copy hood. Couldn't be happier.

jimr-pdx · 07-17-2010, 06:48 AM

I've a copy of the Tamron 70-300 LD on my Sony. Images are nice but its relative focus speed put it on the shelf. The K-7 is faster to focus overall than my A200 so hard to say how a Tamron would compare to 55-300 in speed.. but it was the slowest-focus lens in my Sony bag so I usually grabbed my 100-200 instead.

I now have the DAL version of 55-300; its range wins, IQ is great but I don't need 1:2 'macro' which might be of interest to some buyers. It's definitely smaller than the Tamron, weight is similar. I would say the focus is a bit .. whiny .. with the DAL, a bit more annoying than the DA 16-45. The bokeh has not been as nice as the Tamron either, but I've only had a few days with the 55-300 so am still learning its highs & lows. I expect I'll miss the manual-focus override at times that the DA models have, but otherwise it's quite nice - and I found a good price for a new copy. For lo-light tele I've a man-focus 135/2.8, as bpjod notes a prime like that is nice to have at times.

Last edited by jimr-pdx; 07-17-2010 at 06:50 AM. Reason: it's better now

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07-15-2010, 06:48 PM	#31
photogerald Senior Member Join Date: Sep 2009 Posts: 253	Originally posted by Laurentiu Cristofor Strange - the note and the second list you provided seem to contradict each other. In the list, if I am reading it right, there are several HSM lenses that are marked as working on Pentax. It's true that the 70-200 MACRO HSM is marked as not working, but other HSM lenses are shown to keep AF with the teleconverters. Looks like their guidance is a mess anyway. That list is indeed confusing to read, now that you mention it. I believe the ones listed as "EX DG / HSM" in the table only had HSM in other mounts besides Pentax. For example, the "APO 100-300mm F4 EX DG / HSM". I have the 1.4x matched converter and there's no way it would work with HSM/SDM as it lacks the PZ contacts.

07-16-2010, 04:58 AM	#32
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	Originally posted by Pentaxor I think it would just be a matter of time where slow lenses would be as capable as fast lenses in such demanding situations..... Not trying to pick a fight here, but I think we are not all that far away from theoretical limits. Last time I looked, sensors were about a factor of three below theoretical quantum efficiency limits - I think that included the Bayer filter strategy. At the quantum efficiency limit, only software tricks can further improve S/N ratios (like an algorithm that decides "this area is sky & the sky has no noise"..etc..) I suspect it may not be long before the remaining 2 stops sensitivity are picked up by sensor and software design, but there are practical limits not far away. Dave

07-16-2010, 02:34 PM	#33
yoshizuki Forum Member Join Date: Jan 2010 Photos: Gallery Posts: 74	the 55-300 is probably the best value for the money. It can have slow focus, but anything better, like the sigma 2.8s, come with a significant higher price and weight. I have the DAL version and bought a cheap copy hood. Couldn't be happier.

07-17-2010, 06:48 AM	#34
jimr-pdx Pentaxian Join Date: May 2010 Location: now 1 hour north of PDX Photos: Gallery \| Albums Posts: 3,897	I've a copy of the Tamron 70-300 LD on my Sony. Images are nice but its relative focus speed put it on the shelf. The K-7 is faster to focus overall than my A200 so hard to say how a Tamron would compare to 55-300 in speed.. but it was the slowest-focus lens in my Sony bag so I usually grabbed my 100-200 instead. I now have the DAL version of 55-300; its range wins, IQ is great but I don't need 1:2 'macro' which might be of interest to some buyers. It's definitely smaller than the Tamron, weight is similar. I would say the focus is a bit .. whiny .. with the DAL, a bit more annoying than the DA 16-45. The bokeh has not been as nice as the Tamron either, but I've only had a few days with the 55-300 so am still learning its highs & lows. I expect I'll miss the manual-focus override at times that the DA models have, but otherwise it's quite nice - and I found a good price for a new copy. For lo-light tele I've a man-focus 135/2.8, as bpjod notes a prime like that is nice to have at times. Last edited by jimr-pdx; 07-17-2010 at 06:50 AM. Reason: it's better now