Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-14-2010, 09:11 AM   #16
Junior Member




Join Date: Jul 2009
Photos: Gallery
Posts: 27
But if the 'pancake design' is actually a superior design, then why aren't all lenses pancakes?

01-14-2010, 09:14 AM   #17
Veteran Member




Join Date: Jan 2009
Location: Canada
Posts: 1,255
QuoteOriginally posted by Scrib Quote
But if the 'pancake design' is actually a superior design, then why aren't all lenses pancakes?
Because as with everything in photography there are trade-offs. If you want large aperture and a sharp image wide open (correcting for spherical and chromatic aberration), you need a giant front element and a lot of optical elements in between. Take a look at Sigma 50 f/1.4. The small lenses are comparatively slow.
01-14-2010, 12:53 PM   #18
Veteran Member
Laurentiu Cristofor's Avatar

Join Date: Nov 2009
Location: WA
Photos: Albums
Posts: 3,044
Also check this reference, for the earliest pancake lens design:

Tessar - Wikipedia
01-14-2010, 12:59 PM   #19
Veteran Member




Join Date: Sep 2008
Location: New Jersey, USA
Posts: 337
Awesome form-factor and performance. Many people can better speak to the technical merits. Practically, in addition to the benefit of making your subjects more comfortable, I have found that when I have to hand my camera off for a shot, the other person (usually my wife) seems more at ease. When I hand her my K200D with my Tamron 28-75, or god forbid my Pentax 50-135, between the size, and the weight, and using the zoom (not flicking a lever like on a P&S), it's usually a lost cause. But when I hand her my K200D with my DA 40 or DA 70, it is small, and light, and I say "no zoom--what you see is what you get", she just shoots away and usually gets good shots.

01-14-2010, 01:57 PM   #20
Forum Member




Join Date: Nov 2009
Location: Southern California
Posts: 51
The Pentax "pancake" primes was the primary reason I bought into the Pentax system, which is quite a change for me, since I had given up on using primes in the past because of their inconvenience - more lenses to carry and more work to use. The ability to pocket 2 or 3 primes covering a useful range of focal lengths, along with the already compact, feature-rich K-7 makes it terrific on-the-go/travel/walk-around system.



When I need a zoom due to limited maneuverability or convenience, I'll take my D700 and 24-70 or 17-35 - but that adds more weight. There would be other reasons I'd use the D700 over the K-7, but that's another topic.

I started with the 40mm, then bought into the rest of the set, once I realized its performance fit my needs in terms of usage and output. Needless to say, I was very impressed with the 40mm - it is amazingly small with excellent overall image quality. I just started to compare the DA 70mm to my Nikon 105DC and thus far, they seem quite comparable in terms of image quality. I haven' t used the 15 or 21 very much yet, so can't comment on those. I like the size of the 21 more so than the 15, however. The 15, while still relatively small, isn't what I'd call a true pancake.
01-14-2010, 02:20 PM   #21
Site Supporter




Join Date: Jun 2008
Location: McLean, VA
Photos: Gallery
Posts: 78
Jeffrey R makes a very good point.

Sometimes I use my K7 with zooms (DA* 16-50, 50-135, and 55-300).
I usually have the grip in place for those and they are very comfortable.
Other times I'll just take the K7 without the grip and two (or three) limiteds for a very compact experience. I find the primes to be very sharp. While the DA limiteds may not be as fast as their counterparts, the FA limited are both fast and sharp.
I have the FA43 which is a 1.9 and I hope to someday get the FA31 limited which is a 1.8. While they are small, they are not "pancake" in size like the DA 40 is.
In addition to the FA43, I have the DA 21 and DA 70. I use the DA 70 for portraits and as others have said, it makes the subject more comfortable that a larger lens. The Da 21 has been a pretty good walk-around lens when I want to stay small and discreet. I keep trying to convince myself that I need the 31 to complete the package.

David
01-14-2010, 03:04 PM   #22
Senior Member
Frank B's Avatar

Join Date: Aug 2009
Location: San Diego, California
Posts: 149
QuoteOriginally posted by little laker Quote
Since you've heard about some, although probably not all of the advantages already I'll mention the only 2 downfalls of it.... that I can think of. Since I don't own one I'm just basing this on what I've heard
1. They're harder to focus manually, due to being soo close to the body.
2. Much easier to get your finger in the shot. I've seen this a couple of times in the lab, where I work.
Other than that, I understand that they're stellar lenses. I'd like to add one to my collection soon.
Since you mentioned that your comments were based on what you've heard - I have the DA15, DA21, DA40 and DA70, and can say from personal experience:

1. In actual use the DA Ltd lenses (including the DA40) are not at all difficult to focus manually, or at least not any more so than any other AF lens. You just have to get used to holding the camera and lens in the appropriate manner for a lens that short. Actually they have a pretty nice feel to manual focus when compared to the older F lenses like the 35 f/2 or 50 f/1.4.

2. I think you would really have to not be paying attention to get your finger in the shot with a DA Ltd, even with the DA40. Now, if you want to talk about fingers (and other body parts) in the shot with the DA10-17 Fisheye that's a whole different story.
01-14-2010, 03:28 PM   #23
Site Supporter
GeneV's Avatar

Join Date: Oct 2008
Location: Albuquerque NM
Photos: Albums
Posts: 9,775
QuoteOriginally posted by jonlee Quote
The Pentax "pancake" primes was the primary reason I bought into the Pentax system, which is quite a change for me, since I had given up on using primes in the past because of their inconvenience - more lenses to carry and more work to use. The ability to pocket 2 or 3 primes covering a useful range of focal lengths, along with the already compact, feature-rich K-7 makes it terrific on-the-go/travel/walk-around system.



When I need a zoom due to limited maneuverability or convenience, I'll take my D700 and 24-70 or 17-35 - but that adds more weight. There would be other reasons I'd use the D700 over the K-7, but that's another topic.

I started with the 40mm, then bought into the rest of the set, once I realized its performance fit my needs in terms of usage and output. Needless to say, I was very impressed with the 40mm - it is amazingly small with excellent overall image quality. I just started to compare the DA 70mm to my Nikon 105DC and thus far, they seem quite comparable in terms of image quality. I haven' t used the 15 or 21 very much yet, so can't comment on those. I like the size of the 21 more so than the 15, however. The 15, while still relatively small, isn't what I'd call a true pancake.
Same reason I was buying the predecessors 30 years ago. You could pop an MX body or even two with compact M-lenses on them in a bag, and never need a zoom. Except for the K-7 on the body, that looks a lot like the rig I took all over. Even the new form of the K-7 is in line with what I liked about the Pentax line of the early 80s.

01-14-2010, 03:33 PM   #24
Veteran Member
Gooshin's Avatar

Join Date: Sep 2007
Location: Toronto, the one in Canada.
Posts: 5,611
QuoteOriginally posted by Scrib Quote
I've been wondering about this as well. The advantage is obviously that they are small, but doesn't IQ suffer from this? I mean, I can't imagine Pentax stuffs all the expensive glass in the larger lenses just for fun. I'd think there is always a compromise... then again, I don't know much about optics.
the compromise is maximum aperture

the FA31 is F1.8, the DA40 is F2.8

Next time you have an F1.8 lens in your hand, stop it down to F2.8 and you realize how little glass you require.

also the reason Pentax gets away with having pancake autofocus lenses is due to the in-body motor and in-body stabalization.. since these no longer have to be in the lens!

In fact, take the FA31mm or the FA77mm lenses and compare them to any Canon or Nikon equivalent.. (remember they have to cover full frame), the size differences are still noticable.
01-14-2010, 03:42 PM   #25
Pentaxian




Join Date: Feb 2009
Location: Alameda, CA
Posts: 3,198
See how compact they can be - replacing the DA 21mm's and the DA 70mm's hood with something simlar to the DA 40mm's hood and using double lens mount caps:




Last edited by SOldBear; 01-14-2010 at 03:47 PM.
01-14-2010, 04:42 PM   #26
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
A couple of other points:

For the most part, no, you haven't seen other lenses in the same focal length that were bigger - who makes a 21mm or 40mm that is *not* a pancake?

The two commonly cited tradeoffs are maximum / center sharpness and maximum aperture. that is, pancakes might be sharper overall - sharp wide open, sharp in the corners - but when you get down to it, other designs might be sharper in the center when stopped down. And as mentioned, pancakes are typically not as "fast" as larger designs.

A nice side bonus of smaller size is faster AF. MF might not be as nice as with larger lenses, but really, all AF lenses are pretty compromised in that respect, and I don't find even the 40 that much harder to focus manually than any other AF lens I've used. I rather liek that I can focus it with just one finger on my *right* hand.
01-14-2010, 07:02 PM   #27
Loyal Site Supporter




Join Date: Jun 2009
Location: Tumbleweed, Arizona
Photos: Gallery | Albums
Posts: 5,107
QuoteOriginally posted by Reportage Quote
with the Kx, it fits inside ladies purse?
It all depends on the size of the ladies purse....

Its a relative small SLR, but I have seen small purses - no, and large purses - maybe.
I think your mileage may vary...


... my wife's purse - yes, if she emptied everything else out of it...
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!
k-mount, lenses, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
SMC Pentax-M 40mm F2.8 "pancake" lens luckinpentax Pentax SLR Lens Discussion 18 12-16-2009 10:21 AM
The "Other" True Pancake Adam Pentax SLR Lens Discussion 1 08-20-2007 02:54 AM
Purpose of "Checked Images" in Photo Browser. camperguy01 Photographic Technique 1 12-07-2006 04:48 AM
DA 70mm f/2.4 "pancake" sample images Gio645 Pentax SLR Lens Discussion 3 10-22-2006 11:37 PM



All times are GMT -7. The time now is 05:43 PM. | 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