Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-21-2014, 05:28 AM   #1
Senior Member
kentishrev's Avatar

Join Date: Jan 2014
Posts: 180
50mm decision in 30 minutes

Hi all. Looking for some speedy thoughts....

I have the chance to pick up a SMC A 50mm f1.7 today. I already own feh 'current' 50mm AF f1.8.

I don't mind manual focus, but only keen on buying if there is a genuine difference between the two in images.

Should I buy the A lens?

05-21-2014, 05:36 AM   #2
Veteran Member
GabrielFFontes's Avatar

Join Date: Jul 2011
Location: Rio de Janeiro, Brazil
Posts: 647
I wouldn't get it, no. Unless you want to try out MF.
Both have 6 elements in 5 groups, i would guess the only difference would be that the DA 50mm 1.8 would be better in digital cameras due to newer coating.
05-21-2014, 05:39 AM   #3
Veteran Member
lguckert79's Avatar

Join Date: Jun 2010
Location: Pittsburgh, PA
Photos: Gallery | Albums
Posts: 588
From what I have read they built the f1.8 based on the element design of the f1.7 lens and there is not much difference.
05-21-2014, 06:44 AM   #4
Pentaxian
ChristianRock's Avatar

Join Date: Jul 2013
Location: Woodstock, GA
Photos: Gallery | Albums
Posts: 4,532
If you use a hood on the 50 1.8, then they should be about the same. The new design is supposedly less sharp/contrasty wide open, because the front element is more exposed. The older M and A 50 1.7 have the front element more recessed into the lens barrel, so it's sharper wide open because it kind of has a "permanent hood".

YMMV... and all that.

Having said that, I had the A 50 1.7 and sold it because I liked my M 50 1.7 better - yet they're supposed to be pretty much identical. So there's always sample variation with these lenses, especially the older ones... if it's cheap, why not get it - it might be a good one. If it isn't, sell it for what you paid for it

05-21-2014, 07:28 AM   #5
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,445
I own both lenses and they are definitely different,* though it is a matter of taste which one a person might prefer. As for claims of shared design...Yes, both are Planar design and both have the same number of elements, but that is true for most Japanese-designed 50mm lenses at f/1.7, f/1.8 and f/2 maximum aperture since the mid-1950s.** I am with ChristianRock and suggest that there is no harm in making the purchase, if for no other reason than to satisfy your curiosity.

As for physical comparisons, the front element of the DA 50/1.8 actually sits deeper in the lens face than that of the A 50/1.7 at infinity and about the same at minimum focus distance. I use a hood with both lenses. Manual focus is easier and more gratifying on the A 50/1.7 due to a wider and nicer focus ring. Both lenses are light and compact with the DA being lighter and the A being smaller. Both handle nicely on my Pentax dSLRs. At some point (when I get really bored) I will probably do a comparison between the A 50/1.7, the K 55/1.8 and the DA 50/1.8 on both digital and film.


Steve

* My impression is that the DA 50/1.8 may be a little sharper than the A 50/1.7. Bokeh is different, not better, but different. The DA also tends to have a sort of "glow" around high-contrast highlights.

** The number of groups is usually 5, though the number of elements may be 5 or 6 with the better lenses having 6. The difference between lenses is more in the implementation details and less in the high-level design.

Last edited by stevebrot; 05-21-2014 at 08:09 AM.
05-21-2014, 07:57 AM   #6
Pentaxian
ChristianRock's Avatar

Join Date: Jul 2013
Location: Woodstock, GA
Photos: Gallery | Albums
Posts: 4,532
QuoteOriginally posted by stevebrot Quote
At some point (when I get really bored) I will probably do a comparison between the A 50/1.7, the K 55/1.8 and the DA 50/1.8 on both digital and film.


Steve.
Please get bored soon, Steve

Regarding the DA 50 1.8 having the front element more exposed, this was mentioned here a few times, but since you have both lenses, I'm thankful for your debunking of this myth

I don't need a hood with my M 50 1.7 by the way - I've taken pictures wide open in bright sulight and contrast or sharpness loss wasn't a problem - pics turned out very sharp in the in-focus area, in fact! But maybe I should have tried a hood with my A 50 1.7 before I sold it. Maybe that would have been the reason why I didn't like it as much...
05-21-2014, 09:45 AM   #7
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,445
QuoteOriginally posted by ChristianRock Quote
Please get bored soon, Steve
Soon enough, I expect. As for the front element exposure, there is truth and there is Internet truth...'nuff said


Steve
05-21-2014, 11:30 AM   #8
Pentaxian
ChristianRock's Avatar

Join Date: Jul 2013
Location: Woodstock, GA
Photos: Gallery | Albums
Posts: 4,532
Well, for the DA 50 1.8, I believe that this is at infinity focus:



And here it's focused closer, I assume:



So, I guess it is about the same as the M 50 1.7...



On the 2nd picture, we can see that the FA 50 1.4 does have its front element quite a bit more exposed than the 1.7 fifties. So the reputation of that one for needing a hood is more justified, I guess...

05-21-2014, 12:49 PM   #9
Veteran Member
hongzhibin1987's Avatar

Join Date: Feb 2012
Location: Albuquerque, NM
Posts: 441
DA50/1.8 no brainer.
05-21-2014, 11:28 PM   #10
Senior Member
kentishrev's Avatar

Join Date: Jan 2014
Posts: 180
Original Poster
Thanks for all the advice. The lens is still in the shop, and I am 40 better off. I'll carry on saving for my 100mm WR macro.

Of course.....if it's still there on Saturday.......
05-22-2014, 08:03 AM   #11
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,445
QuoteOriginally posted by kentishrev Quote
I am 40 better off.
I am not up on British lens prices, but 40 is high for an A 50/1.7 on this side of the Atlantic. They generally go for $50 USD or less.


Steve
05-22-2014, 08:27 AM   #12
Loyal Site Supporter
ivanvernon's Avatar

Join Date: Oct 2012
Location: Medina, OH
Photos: Albums
Posts: 2,104
Top ten Pentax lenses

I am wondering of all the lenses that Pentax has produced, which ten you believe to be the best. I personally do not have the experience with enough Pentax lenses to name ten, but certainly I would include the three limiteds, 32, 43, and 77 and maybe the D FA 50 mm f 2.8 macro. Please mention which factors are most important to you--sharpness, color rendering, speed (aperture below 2.0), background blur, ease of use, or whatever you consider importan.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
50mm, 50mm decision, k-mount, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Night I'll Be Home in 20 Minutes... alteredcarbon Pentax K-3 Photo Contest 7 05-09-2014 05:24 PM
I made my decision on the K-30 Lokusart Pentax K-30 & K-50 28 11-13-2013 07:26 AM
Too late by 30 minutes, lost one heck of a deal! bdery Pentax SLR Lens Discussion 4 04-10-2011 09:10 AM
K200d shot time reported by exif 30 minutes behind grun2000 Pentax DSLR Discussion 3 09-11-2010 03:21 PM
My 30 minutes with the Tamron 70-200mm JMS Pentax SLR Lens Discussion 2 04-21-2008 04:11 PM



All times are GMT -7. The time now is 08:03 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top