SMC-M 50mm f.17 sweet spot

[Dubesor]

This is for those of you that have this nice little lens ... what do you find to be the 'sweet spot' aperture for ultimate sharpness? In my limited experiments, I've narrowed it down to somewhere between f4 and f8, which isn't much.

--
Dubesor
http://www.flickr.com/people/dubesor/

 

[Alex 007]

Hello Dubesor,

I acquired a SMC-A 1,4 50mm one & found that at F:4 deliver to my sole opinion such "Sweet Spot" as you named!.

But...may change among examples!

Enjoy your lens forever!

Peace,
--
Alex 007!

 

[pschlute]

I have not done any tests, but experience tells me f8

These sites think so too:

http://www.takinami.com/yoshihiko/photo/lens_test/pentax_normal.html

http://www.cetussoft.com/pentax/resolutn.htm
--
Peter Schluter

http://www.flickr.com/photos/peter_schluter/

 

[Dubesor]

@pschlute: Thanks for the links and the info! I will keep experimenting closer to the f8 stop.

@Alex 007: Your lens is f1.4 (faster than my f1.7) and so has different optics and a different sweet spot.

--
Dubesor
http://www.flickr.com/people/dubesor/

 

[Alex 007]

@pschlute: Thanks for the links and the info! I will keep
experimenting closer to the f8 stop.

@Alex 007: Your lens is f1.4 (faster than my f1.7) and so has
different optics and a different sweet spot.

--
Dubesor
http://www.flickr.com/people/dubesor/

Hi Dubesor!

Yes it's possible if course!

My best wishes...F:8 it's OK for me also!

Enjoy,

Peace,
--
Alex 007!

 

[pschlute]

The M 50mm 1.7 was the first lens I ever purchased. new with a pentax MX. That was 1979 I think. I still use it today.



--
Peter Schluter

http://www.flickr.com/photos/peter_schluter/

 

[Dubesor]

Actually, your photo of the fruit & veg above pretty much convinced me to buy it (I spotted it in another thread on here when doing my research).

--
Dubesor
http://www.flickr.com/people/dubesor/

 

[pschlute]

..and I have just realised I have just added you as a contact on Flickr !
--
Peter Schluter

http://www.flickr.com/photos/peter_schluter/

 

[Alex 007]

Hi,

Tell me WHY a M lens & NOT minimum a A one? If you can a FA...so much easier & accurately on focus that any of both of them???.

Same construction & lens formula...so WILL BE...very similarly final results!

My sincerely advise!

Good luck,

Peace,
--
Alex 007!

 

[daimesu]

Hi Dubesor:

F8 seems to be the sharpest setting on this lens.

My "sweet spot" on the lens is the half-click between 1,7 and 2,0. I think its a good mix of sharpness and boke that works well for portrait-type shots.

• daimesu

This is for those of you that have this nice little lens ... what do
you find to be the 'sweet spot' aperture for ultimate sharpness? In
my limited experiments, I've narrowed it down to somewhere between f4
and f8, which isn't much.

--
Dubesor
http://www.flickr.com/people/dubesor/

--
[ http://www.flickr.com/photos/agis/ ]

 

[Dubesor]

@ Alex 007:

I'm not sure how much the A and FA versions cost, but it's probably more than I can afford. Even the M is typically ~$50 and that's as much as I'll spend on any one lens for the time being

Otherwise, would love to get them.

--
Dubesor
http://www.flickr.com/people/dubesor/

 

[Alex 007]

Hi!

Just found some logical explication!

M Series Lenses: In the early 1980's, Pentax introduced a series of compact, manual focus, lenses designed to accompany the popular ME, ME Super, and MX cameras. These lenses bear the designation "SMC Pentax-M" along with "Ashai Optical Co., Japan."

A Series Lenses: These manual focus lenses have the contacts and aperture ring setting to support program modes - like auotexposure mode or shutter priority. When set to the "A" setting the camera body can control the aperture setting. These lens also support evaluative metering in modern camera bodies. (The K and M series lenses allow only center weighted metering.) The “A” lenses retain full computability with all Pentax Cameras, including the most modern. The prior K and M lenses are not compatible with some newer bodies.

F and FA Autofocus Lenses: Pentax has produced two series of autofocus lenses - the F and FA lines. In many cases, the differences between these two series are primarily cosmetic, with some differences in internal electronics. While some FA zooms support the power zoom function, newer FA zooms do not.

Good Luck,
--
Alex 007!

 

[languid]

For my SMC A 1.7 it is definitely 5.6....
--

 

[viking79]

Good point, as if you shoot portraits you might not find the sharpness at f4 and up appealing! In which case the pleasant softness from 1.4(or 1.7) to 2.8 would be much more appealing.

My 1.4 gets razor sharp by 4 and stays that way for several stops before tapering off slightly. I couldn't really tell a difference, but when I just shot the computer screen, the pixels were sharpest at f4, and tapered off slowly towards f11 or f16 or so and then fell off more rapidly after that.

 

[tuszi]

My copy has it on f/5,6

 

[pentaxiantrooper]

Have you ever used a decent M series lens? Do you autofocus a lot with a 1.4 lens wide open? The Pentax-M f/1.4 50mm has gorgeously smooth focus and i focus manually even when using AF capable lenses, so this matters to me, the only one i can think of that's smoother is the Pentax-M 75-150/4

The M 1.7 is a better lens in many ways though, just not as well built.

 

[Dubesor]

I would love to get the 1.4 for low-light situations and already know it's a great lens. But no need to knock the 1.7 - some others have taken stunning photos with it (eg. see lemon shot above).

What's the point of posting that criticism? It has nothing to do with the question.

--
Dubesor
http://www.flickr.com/people/dubesor/

 

[pentaxiantrooper]

You missed my point entirely, and presumably failed to read my post in context.

As far as M series lenses go the 1.7 is much much sharper wide open and, for me, seems to have better resolution stopped down too, the 1.4 is a larger heavier lens built to higher mechanical standards and with an 8 blade aperture, it has smoother focus than the 1.7 and generally better out of focus highlights, this does not make it a superior lens though, if anything it's slightly disappointing.

The post i replied to suggested getting A series minimum, there are reasons why i would go for the Ms myself, that's all i was trying to explain.

 

[Dubesor]

My mistake. I have the forums in 'flat' view for reading convenience and that makes me sometimes miss who's replying to whom in a thread.

--
Dubesor
my photos @ http://www.flickr.com/people/dubesor/

 

[kww_2007]

My M1.7 was the sharpest at 1.7 and 2.0. Here's a link to my test of the M1.7 at different aperture values:

http://www.photoblog.com/Kentax/2007/12/21/pentax-m-50mm-17.html