Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
11-23-2008, 12:37 AM   #1
Inactive Account




Join Date: Sep 2008
Location: Nanaimo, BC
Posts: 261
A Fast Fifty Is Really A Fast 75mm

This may be a bit if a noob question/theory, but oblige me if you will: considering the crop on all APS-C format cameras (or at least Pentax) of 1.5, our "Fast Fifty" lenses are technically 75mm or so. For those of you who have had your Fifty since you shot film, how have you adjusted to this change? Has the use of your lens changed?

Also, when you take this into consideration, would not a DA Limited 40 be more akin to the original idea behind the "normal" aspect lens, being an equivalent of 60mm? Granted that's at the high end of normal (50-60mm if I understand correctly) but wouldn't it work better for those kinds of shots than, say the new DA*55, which has an equivalent focal range of 82.5mm?

As I'd imagine the DA*55 will be more costly than the DA Limited 40, I figured the comparison was relevant. What are your thoughts?

11-23-2008, 12:57 AM   #2
Senior Member




Join Date: Oct 2007
Location: Geelong
Photos: Gallery
Posts: 138
It makes the 50mm just about useless for my photography.
It isn't a focal length I like using and don't have much need for it.
I have a 28mm which is more generally useful to me, but it's a stop slower.
11-23-2008, 01:37 AM   #3
Igilligan
Guest




if you are looking for that 50mm film perspective

Find a nice 35mm... The FA 35 is F2

Or if the "money is no object" applies in your world... The FA 31 ltd is the ticket.
11-23-2008, 01:45 AM   #4
Forum Member
ariahspam's Avatar

Join Date: May 2008
Location: Lima, Peru
Posts: 69
A fast 50, in aps-c would be looking at the 28-35mm range. And it is true they aren't as fast, cheap and widespread as the film 50's. The closest would be sigma 30mm 1.4.

The DA*55 is designed to be a portrait lens, mimicking the film 85mm.

11-23-2008, 01:48 AM   #5
Veteran Member
Sean Nelson's Avatar

Join Date: Sep 2008
Location: Vancouver BC Canada
Posts: 353
QuoteOriginally posted by drewdlephone Quote
A Fast Fifty Is Really A Fast 75mm
There's enough confusion going around regarding what the "crop factor" really means that I think this is a misleading statement. I would phrase it as "A Fast Fifty really has a 75mm field of view".

I usually use my SMC-M 50mm f/1.4 only when I have a special need to restrict depth of field at longer subject distances. As you alluded, I find that it's frequently too long to use in low light situations since these are often indoors where it's difficult to back up far enough to frame the subject. But it is terrific for head-and-shoulder shots.

I recently bought the DA35mm macro limited and it's become my "normal" lens. It's a terrific lens, and while I'm not exactly a macro photographer I really love the fact that the lens has for all intents and purposes no limit on how close I can focus.

For low-light indoor shots I usually find myself using the DA35 or DA12-24. While slower than the fast fifty, the wider field of view (which makes hand-held shots easier) and the ability to shoot up to about ISO 800 with no appreciable noise means that I don't miss the faster lens all that much.
11-23-2008, 02:42 AM   #6
Inactive Account




Join Date: Sep 2008
Location: Nanaimo, BC
Posts: 261
Original Poster
QuoteOriginally posted by Igilligan Quote
Find a nice 35mm... The FA 35 is F2

Or if the "money is no object" applies in your world... The FA 31 ltd is the ticket.
I'll keep an eye out for the first one. Would it end up being as good, optically, as the DA Limited 40?

QuoteOriginally posted by Sean Nelson:
here's enough confusion going around regarding what the "crop factor" really means that I think this is a misleading statement. I would phrase it as "A Fast Fifty really has a 75mm field of view".

I usually use my SMC-M 50mm f/1.4 only when I have a special need to restrict depth of field at longer subject distances. As you alluded, I find that it's frequently too long to use in low light situations since these are often indoors where it's difficult to back up far enough to frame the subject. But it is terrific for head-and-shoulder shots.

I recently bought the DA35mm macro limited and it's become my "normal" lens. It's a terrific lens, and while I'm not exactly a macro photographer I really love the fact that the lens has for all intents and purposes no limit on how close I can focus.
It wasn't my intention to muddy unclear waters, but I thought it interesting to bring up a topic that I've never seen discussed, in person or otherwise. I find my Tak 55/1.8 is just about useless for anything except portrait shots, and for that, it excels. Taking low light shots of my cats or indoors just doesn't work as well as I'd like.
11-23-2008, 03:00 AM   #7
Igilligan
Guest




well I would trade...

I have the DA 40 and I like it fine. But if I wanted the field of view of the old 50mm on film, and I wanted it a little faster, I would swap my DA 40 for the FA 35 or Da 35. The FA 35 is F2 and pretty darn sharp at f2.
Some folks say the DA 35macro is one of the finest lenses out there right now... So take a look at that one too.

But the Da 40 does have a 'look'.

Last edited by Igilligan; 11-23-2008 at 09:52 AM.
11-23-2008, 09:19 AM   #8
Pentaxian
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 10,132
I think it is important for people to try to get away from this focal length equivalency crutch and start thinking in terms of what focal lengths do on the format they are using rather than some format they are not using.

Your 50mm lens is technically a 50mm lens. Nothing has changed with the lens, so how has the focal length suddenly become "75mm or so"?
The standard focal length on the APC-C format DSLR cameras that we use is ~28mm, so the closest thing that Pentax makes to a normal lens is the 31/1.8. I suspect that if the 30mm project ever sees the light of day, the 31 will go out of production.
The 30mm had better be an f/1.4, though with Pentax's propensity for making slow primes, I'm not holding out much hope.....

As far as what has changed for me with the move to digital, my 50mm lenses are now portrait lenses, my 35mm lenses are now my standard lenses, etc.

What hasn't changed for me is the way I think about focal lengths. Whan I shot 3 different film formats, my 50mm lens was not a 24mm lens, nor was it a 17mm lens. My 105mm lens was not a 50mm lens, nor was it a 35mm lens. My 150mm lens was not a 90mm lens, nor was it a 50mm lens.
And if you find the above to be a bit confusing, you might perhaps realize why I think the whole multiplication factor thing is a really stupid way to think about focal lengths.
Learning what a focal length does on the format being shot is more than just doing some arithmetic in your head.

11-23-2008, 09:33 AM   #9
Veteran Member
roentarre's Avatar

Join Date: Oct 2006
Location: Melbourne, Australia
Posts: 11,794
Still 50mm will have the perspective of the 50mm instead of 75mm
11-23-2008, 09:51 AM   #10
Veteran Member
Venturi's Avatar

Join Date: Mar 2008
Location: Tulsa, OK
Photos: Gallery
Posts: 2,639
QuoteOriginally posted by Wheatfield Quote
Your 50mm lens is technically a 50mm lens. Nothing has changed with the lens, so how has the focal length suddenly become "75mm or so"?
Thank you!

The whole "crop factor" thing has probably caused more confusion and generated more mis-information than any other subject in the history of photography. I know it baffled me for months until I figured out how to ask the question properly.

Crop factor is nothing more than marketing speak and so is "full frame", no matter how anyone tries to rationalize it. In the 6x4.5 film world do we refer to 220 film as "full frame" and 120 film as "cropped"? No. Do they record a different field of view when paired with same focal length lenses? Yes.
An APS-C (23mm) sensored camera is NOT a 35mm camera. Most of them use the same lens mounts as their same branded 35mm cameras. That's it. Mystery solved.
11-23-2008, 10:18 AM   #11
Veteran Member
jsherman999's Avatar

Join Date: Dec 2007
Photos: Gallery
Posts: 8,228
QuoteOriginally posted by Venturi Quote
Thank you!

The whole "crop factor" thing has probably caused more confusion and generated more mis-information than any other subject in the history of photography. I know it baffled me for months until I figured out how to ask the question properly.

Crop factor is nothing more than marketing speak and so is "full frame", no matter how anyone tries to rationalize it. In the 6x4.5 film world do we refer to 220 film as "full frame" and 120 film as "cropped"? No. Do they record a different field of view when paired with same focal length lenses? Yes.
An APS-C (23mm) sensored camera is NOT a 35mm camera. Most of them use the same lens mounts as their same branded 35mm cameras. That's it. Mystery solved.

The whole reason this persists is because many people spent years getting used to the FOV of 35mm lenses on film bodies - what to expect to see in the frame when you put a certain lens on.

So I don't think it's surprising to realize that a FOV conversion procedure needs to happens in people's heads still, it's natural.

I never really shot 35mm film SLRs, so to me, a 50mm is a 50mm is a 50mm, but if I had shot film, it would probably take me a little while to get used to 'seeing' in the new FOV vernacular, and discussion of crop factor would be pertinent.


.
11-23-2008, 10:27 AM   #12
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
As someone who *didn't* come from a lot of experience with film:

Yeah, 50mm doesn't seems a generally useful focal length. Nice for some kinds of portraits, and the wide aperture is nice for that too. But otherwise, when it comes to low light, ISO 1600 performance from modern DSLR's is good enough that one could claim f/2.8 is the new f/2.0, even f/1.4. Maybe I just don't know what I'm missing, but it seems that with a 28/2.8 and/or a 40/2.8, I can do most of what used to be possible with a 50/1.4.
11-23-2008, 10:34 AM   #13
Inactive Account




Join Date: Oct 2007
Location: Brisbane, QLD, AUS
Posts: 3,262
Aw, ferf*cksakes...

We just got the lid back on this can of worms!
11-23-2008, 10:39 AM   #14
Veteran Member
troyz's Avatar

Join Date: May 2008
Posts: 389
QuoteOriginally posted by drewdlephone Quote
This may be a bit if a noob question/theory, but oblige me if you will: considering the crop on all APS-C format cameras (or at least Pentax) of 1.5, our "Fast Fifty" lenses are technically 75mm or so. For those of you who have had your Fifty since you shot film, how have you adjusted to this change? Has the use of your lens changed?
Well, it's been a few weeks since I shot film. . . let me think. . .

(1) I use a different lens as my "fast normal" lens on APS-C (I use an FA31; the FA35 would be my second choice and I also read good things about some of the 28s)

(2) I have to subtract one f-stop from the DOF scale on FA lenses when I'm using APS-C (e.g. use the f/5.6 marks when shooting at f/8)

50-ish lenses are still great for APS-C; you'll just get a tighter composition (if you don't move away from your subject) or different perspective (if you do move away from your subject) than you would get from film.

BTW, for the indoor shots on the Tak 55 try ISO 800 f/2.8 or so. ISO 1600 for moving subjects.
11-23-2008, 10:47 AM   #15
Veteran Member
Venturi's Avatar

Join Date: Mar 2008
Location: Tulsa, OK
Photos: Gallery
Posts: 2,639
QuoteOriginally posted by lithos Quote
Aw, ferf*cksakes...

We just got the lid back on this can of worms!


Yeah well... I'm guessing there's no way to weld the can shut though.
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!
75mm, da, da*55, equivalent, fifty, k-mount, lens, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
What's a FAST (used to be fast) film lens neverbnnba Pentax SLR Lens Discussion 11 07-03-2010 05:42 PM
Fast fifty vs. fa 35 f/2.0? Deni Pentax SLR Lens Discussion 30 04-03-2009 07:58 PM
that's why we call it fast fifty - fa 50mm f/1.4 fearview Pentax SLR Lens Discussion 8 06-18-2008 12:54 AM
Fast fifty proudtoshootpentax Pentax SLR Lens Discussion 18 05-08-2008 10:59 PM



All times are GMT -7. The time now is 02:59 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