A 50mm/f1.4 vs M 50mm/f1.4?

jtkratzer · 10-18-2012, 08:00 PM

I had both until I recently sold the M lens, which inconveniently took place right before I was given an ME Super. I've been using the A 50 on the ME Super and was wondering if it was worth keeping my eyes open for an M 50/1.4 or 1.7. I kept the A as it was great to use on the K-5 without having to use the green button or otherwise to meter like I had to with the M and the A 50 is nice for video.

So, is there much of a difference optically between these three that it'd be worth picking one up? I'd prefer to grab a 28mm lens first, just saw a K 28/f3.5 go from about $40 to $114 on eBay in less than an hour as the auction closed. Didn't want to pay that much, but I'd like to get something wider than the 50mm that has a nicer focusing ring than the FA 28-80 that came on my ZX-30 10 years ago.

**Just1MoreDave** · 10-18-2012, 09:27 PM

The K, M and A 50mm f1.4 optical formulas are all different, but it's hard to even see on an optical diagram. At some point, you have to draw the line on 50s. OK, I haven't done that successfully myself but it's still good advice.

lytrytyr · 10-19-2012, 12:50 AM

Originally posted by Just1MoreDave

The K, M and A 50mm f1.4 optical formulas are all different, but it's hard to even see on an optical diagram.

If you look at the diagrams on Boz Dimitrov's site:
Pentax Normal Prime Lenses
comparing the M50/1.4 with the A50/1.4,
the curvature of the join in the cemented pair
(just behind the aperture blades)
is noticeably sharper on the A than on the M.

Don't know if this makes the M perform better at infinity (I don't have an A to compare).

Originally posted by Just1MoreDave

At some point, you have to draw the line on 50s. OK, I haven't done that successfully myself but it's still good advice.

Yeah, yeah. (I only have 6 that will mount on a K-5.)

Jonathan Mac · 10-19-2012, 01:13 AM

The M 50 1.4 is a good lens but will probably cost at least double what a 1.7 will. I like the 1.7 version more. I'd say a 1.7 is worth picking up, because it can be bought easily and cheaply, while a 1.4, if you already have one, will not be as useful for the money you'll need to spend.

jtkratzer · 10-19-2012, 04:15 AM

It's unfortunate that I sold my M50/1.4 that was in great shape, but at the time, I had that, the A50/1.4 and an F50/1.7.

bricamry · 10-19-2012, 05:53 AM

imho all 50s are same optics K, M, A, F, FA... only diferent case and diff SMC...
if you want use only MF and have good handling, A version is good choice... solid build. yes, if you will save money, buy A50/1,7 it is good too... but 50/2 is bad choice, soft, soft, soft... @F2 very soft.... but A50/1,4 is awesome... see my photo @F2 Snímek z alba Trojice - bricamry.cz

)

for video... i used A28/2,8 and wide open is awesome for that purpose

) yes that lens have spherical DOF, but for video it not matter... it have nice bokeh and sharpnes is comfortable

(this crap

You Tube

is made with that lens, but stopped down for better DOF

)

i hope, that my post helps

jtkratzer · 10-19-2012, 09:27 AM

The camera came with an M50/2 and I haven't put it on the camera since taking it off for the A50/1.4. A 35 or 28mm lens is probably higher on the list, as is gathering up the stuff to develop my film before buying another 50. I'll just keep an eye out for a deal on one.

And then there's the comparison of the A28/2.8 vs K28/3.5...

10-18-2012, 08:00 PM	#1
jtkratzer Veteran Member Join Date: Jul 2012 Location: Lancaster County, Pa Posts: 963	A 50mm/f1.4 vs M 50mm/f1.4? I had both until I recently sold the M lens, which inconveniently took place right before I was given an ME Super. I've been using the A 50 on the ME Super and was wondering if it was worth keeping my eyes open for an M 50/1.4 or 1.7. I kept the A as it was great to use on the K-5 without having to use the green button or otherwise to meter like I had to with the M and the A 50 is nice for video. So, is there much of a difference optically between these three that it'd be worth picking one up? I'd prefer to grab a 28mm lens first, just saw a K 28/f3.5 go from about $40 to $114 on eBay in less than an hour as the auction closed. Didn't want to pay that much, but I'd like to get something wider than the 50mm that has a nicer focusing ring than the FA 28-80 that came on my ZX-30 10 years ago.

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10-18-2012, 09:27 PM	#2
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	The K, M and A 50mm f1.4 optical formulas are all different, but it's hard to even see on an optical diagram. At some point, you have to draw the line on 50s. OK, I haven't done that successfully myself but it's still good advice.

10-19-2012, 12:50 AM	#3
lytrytyr Pentaxian Join Date: Nov 2011 Photos: Gallery \| Albums Posts: 4,310	Originally posted by Just1MoreDave The K, M and A 50mm f1.4 optical formulas are all different, but it's hard to even see on an optical diagram. If you look at the diagrams on Boz Dimitrov's site: Pentax Normal Prime Lenses comparing the M50/1.4 with the A50/1.4, the curvature of the join in the cemented pair (just behind the aperture blades) is noticeably sharper on the A than on the M. Don't know if this makes the M perform better at infinity (I don't have an A to compare). Originally posted by Just1MoreDave At some point, you have to draw the line on 50s. OK, I haven't done that successfully myself but it's still good advice. Yeah, yeah. (I only have 6 that will mount on a K-5.)

10-19-2012, 01:13 AM	#4
Jonathan Mac Pentaxian Join Date: Apr 2009 Location: Madrid, Spain Posts: 10,894	The M 50 1.4 is a good lens but will probably cost at least double what a 1.7 will. I like the 1.7 version more. I'd say a 1.7 is worth picking up, because it can be bought easily and cheaply, while a 1.4, if you already have one, will not be as useful for the money you'll need to spend.

10-19-2012, 04:15 AM	#5
jtkratzer Veteran Member Join Date: Jul 2012 Location: Lancaster County, Pa Posts: 963 Original Poster	It's unfortunate that I sold my M50/1.4 that was in great shape, but at the time, I had that, the A50/1.4 and an F50/1.7.

10-19-2012, 09:27 AM	#7
jtkratzer Veteran Member Join Date: Jul 2012 Location: Lancaster County, Pa Posts: 963 Original Poster	The camera came with an M50/2 and I haven't put it on the camera since taking it off for the A50/1.4. A 35 or 28mm lens is probably higher on the list, as is gathering up the stuff to develop my film before buying another 50. I'll just keep an eye out for a deal on one. And then there's the comparison of the A28/2.8 vs K28/3.5...