Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-30-2016, 10:06 AM   #1
New Member




Join Date: May 2016
Posts: 2
How image quality compares between Pentax 645: FA 45-85 f/4.5 Vs. 55 f/2.8 & 75 f/2.8

Any one has experience with all of these 3 Pentax 645 lenses?

1) Pentax-D FA 645 55mm f/2.8 AL[IF] SDM AW
2) Pentax smc FA 75mm f/2.8
3) Pentax smc FA 645 45-85mm f/4.5

How sharpness, aberrations, colors and contrast of 45-85mm compares with 55mm & 75mm @ f/8 - f/11?

Thanks,

Subrata

05-30-2016, 03:11 PM - 1 Like   #2
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 43,283
I know a lot of people love the zoom, but I've found it to produce softer and more hazy results than the primes. That's just my more or less subjective impression based on photos I've shot, though. Haven't done any controlled tests.

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com's high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

05-30-2016, 04:19 PM - 1 Like   #3
Site Supporter
Site Supporter
gavincato's Avatar

Join Date: Apr 2015
Location: NSW, Australia
Posts: 247
I haven't used the zoom. The 55 is stunning stopped down. I find it a bit of a weird focal length but for me, the actual optics is fantastic. It does get a bit of CA though under extreme backlit scenarios (i.e. sun blazing through tree leaves)
05-30-2016, 06:34 PM - 1 Like   #4
Pentaxian




Join Date: Apr 2013
Location: Brisbane, Australia
Posts: 627
I am waiting for the new 45-85 on the roadmap to be released. I carry both the 28-45 and 80-160 and find myself regularly using 45 and 90-100mm, so the mid range zoom would be great.

I think the 45-85 is ok from 45 to 60, but at the long end it may get soft, just what I've read online.

05-31-2016, 09:25 AM - 1 Like   #5
New Member




Join Date: Dec 2014
Posts: 3
I own and have shot with all three. I haven't done extensive controlled testing between them, so these are my overall impressions from real world use: The 55mm has that micro-contrasty and ultra crisp 'pop' of modern lenses. Great center sharpness and seems to be particularly sharp in closeups, I have some portrait shots where you can see every tiny fiber in clothes or hair, it's just unreal. For landscape it's a little disappointing in that it gets softer towards the edges and I have a feeling isn't quite as sharp center as when close up but I haven't tested this. Not a total deal breaker depending on subject matter, just something to be aware of. The nice thing is that it's very light, quiet, quick AF, and weatherproof. I too find it an odd focal length on crop 645, a little too wide for standard lens use but not wide enough to feel like a true wide, so sadly although I think this lens has a lot going for it, I tend to not use it as much.

The 45-85 is surprisingly sharp for a zoom when stopped down and is my most used lens. It covers a very useful range although I do wish it was a bit longer at the long end for tighter portraits. It's generally 'great enough' such that I don't miss having the super crisp look of one of the newer lenses like the 55mm or 90mm. It's heavy but not overly so and handles well on the camera such that it's easy to just leave it on all the time as the default lens. I really hope this is the next lens update Pentax releases as a DFA with modern glass and all the new features.

The 75mm is also quite sharp and makes a nice longer standard lens. I have some great studio portraits from it that are very sharp. It is of course also very small and light, but it's finicky to manually focus if you need to due to the tiny focus ring. Bonus for being fast at f2.8. It can be a fun walk around town lens when you want to go really light, but I generally I don't find it so much more useful than the 75mm setting on the 45-85mm as it's about the same sharpness/character so I'm more likely to just take the zoom instead and then I have more flexibility.
05-31-2016, 05:15 PM - 1 Like   #6
Pentaxian




Join Date: Apr 2014
Location: Baltimore
Posts: 559
QuoteOriginally posted by md0724 Quote
I own and have shot with all three. I haven't done extensive controlled testing between them, so these are my overall impressions from real world use: The 55mm has that micro-contrasty and ultra crisp 'pop' of modern lenses. Great center sharpness and seems to be particularly sharp in closeups, I have some portrait shots where you can see every tiny fiber in clothes or hair, it's just unreal. For landscape it's a little disappointing in that it gets softer towards the edges and I have a feeling isn't quite as sharp center as when close up but I haven't tested this. Not a total deal breaker depending on subject matter, just something to be aware of. The nice thing is that it's very light, quiet, quick AF, and weatherproof. I too find it an odd focal length on crop 645, a little too wide for standard lens use but not wide enough to feel like a true wide, so sadly although I think this lens has a lot going for it, I tend to not use it as much.

The 45-85 is surprisingly sharp for a zoom when stopped down and is my most used lens. It covers a very useful range although I do wish it was a bit longer at the long end for tighter portraits. It's generally 'great enough' such that I don't miss having the super crisp look of one of the newer lenses like the 55mm or 90mm. It's heavy but not overly so and handles well on the camera such that it's easy to just leave it on all the time as the default lens. I really hope this is the next lens update Pentax releases as a DFA with modern glass and all the new features.

The 75mm is also quite sharp and makes a nice longer standard lens. I have some great studio portraits from it that are very sharp. It is of course also very small and light, but it's finicky to manually focus if you need to due to the tiny focus ring. Bonus for being fast at f2.8. It can be a fun walk around town lens when you want to go really light, but I generally I don't find it so much more useful than the 75mm setting on the 45-85mm as it's about the same sharpness/character so I'm more likely to just take the zoom instead and then I have more flexibility.
I agree with most of what has been said above, but I'll add: for some odd reason, the 55 works out to be a good focal length for me in 645---I am still trying to decide why. I have yet to put it through its paces entirely, but don't underestimate the advantages of weatherproofing! The 45 to 85 is an extremely convenient lens. And the 75 is better than it ought to be---and its LS sibling is even sharper, although is not AF. I have all these lenses.
05-31-2016, 06:01 PM   #7
New Member




Join Date: May 2016
Posts: 2
Original Poster
Thank you all for sharing your experience.

I primarily shoot Credo 50 MFDB with Arca Swiss technical camera. However it is a slow system, and there are situations, where I need to act faster, specifically when light is changing fast and either I need to change the focal length and / or re-compose. Other situation is, when there are some moving object in the scene and I need to click the shutter at very precise moment and may be in rapid succession - like photographing crashing wave etc. Hence, I need a MFDB DSLR.

Phase One's current pricing is ridiculous, or at least I can't afford XF and newer Schneider LS lenses. Hence, I wanted to try Pentax 645z.

I have purchased a 28-45 in "Like New" condition, and waiting for the delivery for like new 45-85 & 75 from eBay - Japan. For landscape, my personal preference is Zoom, so I can do the final composition in the field and no need to crop later. Hence I would like to see how 45-85 performs. If this lens performs well from f/9 to f/13, then I'm good. So I will give it a serious try, before I invest in 55mm prime. 75 f/2.8 I have purchased more for portraits.

Again, thanks for sharing your experience.

Subrata
06-01-2016, 11:40 AM - 1 Like   #8
Pentaxian




Join Date: Feb 2009
Location: Arizona
Posts: 912
The 45-85 for the 645 and the 55-100 zoom for the 67 are the same design type. The 55-100 is proven on the 645D & Z and I would bet the 45-85 would be a winner as well.

06-04-2016, 03:32 PM   #9
Forum Member




Join Date: Apr 2015
Posts: 73
The 45-85 is almost always on my camera. I sold the 55mm because it wasn't very sharp. The 75mm is my only other lens and it's very sharp and quick to focus. At some point I may sell the 55 and get the 150 for portraits.

Last edited by dShelly; 06-06-2016 at 07:20 AM.
06-05-2016, 05:47 PM   #10
Site Supporter
Site Supporter
mikeSF's Avatar

Join Date: Jan 2009
Location: East Bay Area, CA
Photos: Gallery
Posts: 5,706
the D FA55/2.8 is likely the best out of that bunch. it is outstanding
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!
45-85mm, 55mm, 645d, 645z, 75mm, camera, f/2.8, f/4.5, fa, image quality, medium format, pentax, smc
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale - Sold: 645N, 2x 120 backs, FA 75mm f/2.8, FA 45mm f/2.8, A 120mm f/4 macro with cases [SOLD] enoeske Sold Items 12 07-02-2016 06:31 PM
For Sale - Sold: Super Fast Primes - 50 f/1.2, 70 f/2.4, 85 f/1.4, 120 f/2.8 Buceemie Sold Items 8 12-17-2014 12:11 PM
For Sale - Sold: Kiron 28mm f/2.5, Pentax K 45-125 f/4.0, Tokina 28-70 f/2.8-4.3 hinman Sold Items 15 09-12-2008 11:31 AM



All times are GMT -7. The time now is 05:10 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