Best Limited Lens in terms of Price-For-Performance?

Jimbo · 03-12-2008, 09:10 PM

Great Picture twinda1

lastdodobird · 03-13-2008, 03:39 PM

i agree, that's a great shot twinda! Any other photos that would show off the performance of the 31mm more?

selar · 03-13-2008, 04:42 PM

DA70 LTD at f2.4

lastdodobird · 03-13-2008, 06:04 PM

Why oh why do I bring up the PhotoZone reviews just now??

Pentax SMC-DA 21mm f/3.2 AL Limited Review / Test Report
Pentax SMC-FA 31mm f/1.8 AL Limited Review / Test Report
Pentax SMC-DA 40mm f/2.8 Limited Review / Test Report
Pentax SMC-FA 43mm f/1.9 Limited Review / Test Report
Pentax SMC-DA 70mm f/2.4 Limited - Review / Test Report
Pentax SMC-FA 77mm f/1.8 Limited Review / Test Report

Anyway... just some quickstats:

3 limiteds got a "Highly Recommended" stamp from PZ: FA31,DA40 & DA70
3 limiteds have a 4-star "Price/Performance" rating from PZ: DA21,DA40 & DA70

In terms of optical quality, PZ has it like this:
FA31 - 4.5 stars
DA40 & DA70 - 4 stars
FA34 & FA77 - 3.5 stars
DA21 - 3 stars

In terms of mechanical quality, PZ has all limiteds on equal footing at 4.5 stars.

interesting...

lastdodobird · 03-16-2008, 07:20 AM

Does anyone think that having the DA15 (when it comes out) and the DA21 would be redundant?

Gooshin · 03-16-2008, 07:38 AM

Originally posted by lastdodobird

Does anyone think that having the DA15 (when it comes out) and the DA21 would be redundant?

the difference between the FOV of 15 and 21mm is very great, so no... iit would not be redundant.

nostatic · 03-16-2008, 10:37 AM

FA77 ltd, front yard, not much light, a few minutes after purchase

http://nostatic.com/photos/twistLily1024.jpg

lastdodobird · 03-16-2008, 10:42 PM

Originally posted by Gooshin

the difference between the FOV of 15 and 21mm is very great, so no... iit would not be redundant.

Really?

Am I correct in saying that as you go longer, the difference in FOV becomes more negligible?

I mean... is it correct to say that the difference in 15mm and 21mm is greater than the difference between, say, 75mm and 81mm?

Are there any general rules to remember that could be useful regarding FL and FOV?

Kguru · 03-16-2008, 11:23 PM

Originally posted by lastdodobird

I mean... is it correct to say that the difference in 15mm and 21mm is greater than the difference between, say, 75mm and 81mm?

Yes that is correct.
Easier to think in terms of percentage change. 21 over 15 is 1.4 ie. 40% change; whereas 81 over 75 is only 8% change.

Back to the poll, if I leave out the DA40 (due to its exceptionally low price) the 77 and 70 are currently joint 1st. That's quite remarkable.

creampuff · 03-17-2008, 12:56 AM

I'd choose the FA43 & FA77 Limiteds.

FOV increases tangentially. In short, this means that as focal length progressively gets shorter, the field of view increases dramatically. So comparing say a DA 16-45mm versus the Sigma 17-70mm wide angle zooms for example, that 1 mm difference works out to about 10 degrees at the wide end.

Specifically the formula is:

2 x tan-1( l / (2 x f) )

where ' l ' is the length of the frame in the direction that you want the reading and ' f ' is the focal length of the lens.

lastdodobird · 03-17-2008, 01:12 AM

Originally posted by Kguru

Yes that is correct.
Easier to think in terms of percentage change. 21 over 15 is 1.4 ie. 40% change; whereas 81 over 75 is only 8% change.

Back to the poll, if I leave out the DA40 (due to its exceptionally low price) the 77 and 70 are currently joint 1st. That's quite remarkable.

oooh...that's a useful piece of information there.

I put it into a spreadsheet laying out all the limiteds (including the DA15, but excluding the DA35-Macro)

So in terms of percentage-chage, this is what it looks like:

so I dunno... putting it this way, it sure changes my POV about the 15mm and 21mm being redundant... Having both the 31mm & 43mm is even more redundant in terms of %-change compared to the 15mm & 21mm.

Originally posted by creampuff

I'd choose the FA43 & FA77 Limiteds.

FOV increases tangentially. In short, this means that as focal length progressively gets shorter, the field of view increases dramatically. So comparing say a DA 16-45mm versus the Sigma 17-70mm wide angle zooms for example, that 1 mm difference works out to about 10 degrees at the wide end.

Specifically the formula is:

2 x tan-1( l / (2 x f) )

where ' l ' is the length of the frame in the direction that you want the reading and ' f ' is the focal length of the lens.

wow. that looks interesting, but is there any way to simplify it a bit? Do you have an example where you can put values to 'l' and 'f'?

Thanks a lot! This is very informative.

Kguru · 03-17-2008, 04:43 AM

Originally posted by lastdodobird

so I dunno... putting it this way, it sure changes my POV about the 15mm and 21mm being redundant... Having both the 31mm & 43mm is even more redundant in terms of %-change compared to the 15mm & 21mm.

A common approach is spacing FLs by a factor of about 1.5x

Someone has been more precise and suggested 1.4x for wide and 1.8x for tele. You see, the 31/43/77 falls exactly into this mould.

But I hear you argue 31 is not wide to use 1.4x? Well ... it was wide back in film days that the FAs were intended for.

Now with dSLRs 31 is normal, the next tele step up is ... guess what, 31x1.8= 55. Wow wow isn't that coming out soon?

lastdodobird · 03-17-2008, 06:33 PM

Originally posted by Kguru

A common approach is spacing FLs by a factor of about 1.5x

Someone has been more precise and suggested 1.4x for wide and 1.8x for tele. You see, the 31/43/77 falls exactly into this mould.

But I hear you argue 31 is not wide to use 1.4x? Well ... it was wide back in film days that the FAs were intended for.

Now with dSLRs 31 is normal, the next tele step up is ... guess what, 31x1.8= 55. Wow wow isn't that coming out soon?

Very interesting. I've learned quite a bit of info over the last several posts.

So considering that I already have the DA40...

40 * 1.8 = 72 (I'm thinking either the DA70 or FA77 will do the trick for this)
40 / 1.4 = 29 (FA31?)
40 / 1.8 = 22 (DA21?)
40 / 1.5 = 27 (??)

LOL =p

a a i b · 03-17-2008, 06:53 PM

I've got the 21, 31, 43, and 77.

My vote for price/performance went to the 43 and 70 (my guess is that the 70 is really close to the 77).

My favorite lens is the 77, but the 31 never really leaves the camera.

nostatic · 03-17-2008, 07:32 PM

Originally posted by a a i b

My favorite lens is the 77, but the 31 never really leaves the camera.

Well, then does price really matter?

I have a 31mm showing up Wed. The 77mm is my favorite so far...but that is compared to a couple zooms. Thinking seriously about the 21, but I wish the mythical 15mm ltd would appear. I'd love to ditch the 16-45...

View Poll Results: Best Limited Lens in terms of Price-For-Performance?
SMC Pentax-FA 31mm F1.8 AL Limited	28	18.92%
SMC Pentax-FA 43mm F1.9 Limited	31	20.95%
SMC Pentax-FA 77mm F1.8 Limited	44	29.73%
SMC Pentax-DA 21mm F3.2 Limited	13	8.78%
SMC Pentax-DA 40mm F2.8 Limited	52	35.14%
SMC Pentax-DA 70mm F2.4 Limited	44	29.73%
Multiple Choice Poll. Voters: 148. You may not vote on this poll

03-13-2008, 04:42 PM	#33
selar Veteran Member Join Date: Jul 2007 Location: Sydney, Australia Photos: Gallery \| Albums Posts: 2,042	DA70 Limited DA70 LTD at f2.4

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03-12-2008, 09:10 PM	#31
Jimbo Veteran Member Join Date: Dec 2007 Location: Maple Ridge BC Canada Photos: Gallery Posts: 11,368	Great Picture twinda1

03-13-2008, 03:39 PM	#32
lastdodobird Senior Member Join Date: Oct 2007 Posts: 128 Original Poster	i agree, that's a great shot twinda! Any other photos that would show off the performance of the 31mm more?

03-13-2008, 06:04 PM	#34
lastdodobird Senior Member Join Date: Oct 2007 Posts: 128 Original Poster	Why oh why do I bring up the PhotoZone reviews just now?? Pentax SMC-DA 21mm f/3.2 AL Limited Review / Test Report Pentax SMC-FA 31mm f/1.8 AL Limited Review / Test Report Pentax SMC-DA 40mm f/2.8 Limited Review / Test Report Pentax SMC-FA 43mm f/1.9 Limited Review / Test Report Pentax SMC-DA 70mm f/2.4 Limited - Review / Test Report Pentax SMC-FA 77mm f/1.8 Limited Review / Test Report Anyway... just some quickstats: 3 limiteds got a "Highly Recommended" stamp from PZ: FA31,DA40 & DA70 3 limiteds have a 4-star "Price/Performance" rating from PZ: DA21,DA40 & DA70 In terms of optical quality, PZ has it like this: FA31 - 4.5 stars DA40 & DA70 - 4 stars FA34 & FA77 - 3.5 stars DA21 - 3 stars In terms of mechanical quality, PZ has all limiteds on equal footing at 4.5 stars. interesting...

03-16-2008, 07:20 AM	#35
lastdodobird Senior Member Join Date: Oct 2007 Posts: 128 Original Poster	Does anyone think that having the DA15 (when it comes out) and the DA21 would be redundant?

03-16-2008, 07:38 AM	#36
Gooshin Veteran Member Join Date: Sep 2007 Location: Toronto, the one in Canada. Posts: 5,610	Originally posted by lastdodobird Does anyone think that having the DA15 (when it comes out) and the DA21 would be redundant? the difference between the FOV of 15 and 21mm is very great, so no... iit would not be redundant.

03-16-2008, 10:37 AM	#37
nostatic Veteran Member Join Date: Feb 2008 Location: socal Photos: Gallery Posts: 1,575	FA77 ltd, front yard, not much light, a few minutes after purchase http://nostatic.com/photos/twistLily1024.jpg

03-16-2008, 10:42 PM	#38
lastdodobird Senior Member Join Date: Oct 2007 Posts: 128 Original Poster	Originally posted by Gooshin the difference between the FOV of 15 and 21mm is very great, so no... iit would not be redundant. Really? Am I correct in saying that as you go longer, the difference in FOV becomes more negligible? I mean... is it correct to say that the difference in 15mm and 21mm is greater than the difference between, say, 75mm and 81mm? Are there any general rules to remember that could be useful regarding FL and FOV?

03-16-2008, 11:23 PM	#39
Kguru Veteran Member Join Date: Jun 2007 Location: Perth - WestAust Posts: 602	Originally posted by lastdodobird I mean... is it correct to say that the difference in 15mm and 21mm is greater than the difference between, say, 75mm and 81mm? Yes that is correct. Easier to think in terms of percentage change. 21 over 15 is 1.4 ie. 40% change; whereas 81 over 75 is only 8% change. Back to the poll, if I leave out the DA40 (due to its exceptionally low price) the 77 and 70 are currently joint 1st. That's quite remarkable.

03-17-2008, 12:56 AM	#40
creampuff Veteran Member Join Date: May 2007 Location: Singapore Photos: Gallery Posts: 3,953	I'd choose the FA43 & FA77 Limiteds. FOV increases tangentially. In short, this means that as focal length progressively gets shorter, the field of view increases dramatically. So comparing say a DA 16-45mm versus the Sigma 17-70mm wide angle zooms for example, that 1 mm difference works out to about 10 degrees at the wide end. Specifically the formula is: 2 x tan-1( l / (2 x f) ) where ' l ' is the length of the frame in the direction that you want the reading and ' f ' is the focal length of the lens.

03-17-2008, 01:12 AM	#41
lastdodobird Senior Member Join Date: Oct 2007 Posts: 128 Original Poster	Originally posted by Kguru Yes that is correct. Easier to think in terms of percentage change. 21 over 15 is 1.4 ie. 40% change; whereas 81 over 75 is only 8% change. Back to the poll, if I leave out the DA40 (due to its exceptionally low price) the 77 and 70 are currently joint 1st. That's quite remarkable. oooh...that's a useful piece of information there. I put it into a spreadsheet laying out all the limiteds (including the DA15, but excluding the DA35-Macro) So in terms of percentage-chage, this is what it looks like: so I dunno... putting it this way, it sure changes my POV about the 15mm and 21mm being redundant... Having both the 31mm & 43mm is even more redundant in terms of %-change compared to the 15mm & 21mm. Originally posted by creampuff I'd choose the FA43 & FA77 Limiteds. FOV increases tangentially. In short, this means that as focal length progressively gets shorter, the field of view increases dramatically. So comparing say a DA 16-45mm versus the Sigma 17-70mm wide angle zooms for example, that 1 mm difference works out to about 10 degrees at the wide end. Specifically the formula is: 2 x tan-1( l / (2 x f) ) where ' l ' is the length of the frame in the direction that you want the reading and ' f ' is the focal length of the lens. wow. that looks interesting, but is there any way to simplify it a bit? Do you have an example where you can put values to 'l' and 'f'? Thanks a lot! This is very informative.

03-17-2008, 04:43 AM	#42
Kguru Veteran Member Join Date: Jun 2007 Location: Perth - WestAust Posts: 602	Originally posted by lastdodobird so I dunno... putting it this way, it sure changes my POV about the 15mm and 21mm being redundant... Having both the 31mm & 43mm is even more redundant in terms of %-change compared to the 15mm & 21mm. A common approach is spacing FLs by a factor of about 1.5x Someone has been more precise and suggested 1.4x for wide and 1.8x for tele. You see, the 31/43/77 falls exactly into this mould. But I hear you argue 31 is not wide to use 1.4x? Well ... it was wide back in film days that the FAs were intended for. Now with dSLRs 31 is normal, the next tele step up is ... guess what, 31x1.8= 55. Wow wow isn't that coming out soon?

03-17-2008, 06:33 PM	#43
lastdodobird Senior Member Join Date: Oct 2007 Posts: 128 Original Poster	Originally posted by Kguru A common approach is spacing FLs by a factor of about 1.5x Someone has been more precise and suggested 1.4x for wide and 1.8x for tele. You see, the 31/43/77 falls exactly into this mould. But I hear you argue 31 is not wide to use 1.4x? Well ... it was wide back in film days that the FAs were intended for. Now with dSLRs 31 is normal, the next tele step up is ... guess what, 31x1.8= 55. Wow wow isn't that coming out soon? Very interesting. I've learned quite a bit of info over the last several posts. So considering that I already have the DA40... 40 * 1.8 = 72 (I'm thinking either the DA70 or FA77 will do the trick for this) 40 / 1.4 = 29 (FA31?) 40 / 1.8 = 22 (DA21?) 40 / 1.5 = 27 (??) LOL =p

03-17-2008, 06:53 PM	#44
a a i b Veteran Member Join Date: Jan 2008 Location: Brooklyn Photos: Gallery Posts: 315	I've got the 21, 31, 43, and 77. My vote for price/performance went to the 43 and 70 (my guess is that the 70 is really close to the 77). My favorite lens is the 77, but the 31 never really leaves the camera.

03-17-2008, 07:32 PM	#45
nostatic Veteran Member Join Date: Feb 2008 Location: socal Photos: Gallery Posts: 1,575	Originally posted by a a i b My favorite lens is the 77, but the 31 never really leaves the camera. Well, then does price really matter? I have a 31mm showing up Wed. The 77mm is my favorite so far...but that is compared to a couple zooms. Thinking seriously about the 21, but I wish the mythical 15mm ltd would appear. I'd love to ditch the 16-45...