Penta-F/FA 50mm f/1.7 and FA 50mm f/1.4

tim_kayak · 03-29-2011, 04:20 PM

I'm thinking of upgrading my Pentax-A 50mm to an af version. The thing I'd like to know is weather af would be a worthwhile upgrade for me. I bought the lens to use in very low light in a temporary night club and don’t know if an af lens would increase the accuracy of my focusing (I use the 'beep' anyway). Some examples of pic taken with my 'A' lens in very low light can be seen here Xsport International
I particularly had problems taken pics of people in focus.

My other question is how comparable are the F/Fa 1.7 and FA 1.4 'like for like' (ie at 1.7 up)? one reviewer has said that the softness of the 1.4 can be fixed with a hood, anyone else had this experience too?

paperbag846 · 03-29-2011, 04:22 PM

Yes, it can be fixed with a hood. However, at f1.7, the 50mm 1.7 lens is sharper than the 1.4 lens at 1.7. The 50mm 1.7 is the best lens for sharp photos in the lowest light IMHO.

AF will help you if you use center point focus and focus on something bright (a shiny table reflecting light, etc). But you will have to manually focus too, sometimes.

m42man · 03-29-2011, 11:05 PM

Here's a useful comparison of the two lenses (and several others):

Nifty 50 Shootout on Pentax K-7 (updated 1/22) ERPhotoReview

You'll see here that the 50/1.4 is surprisingly soft at f1.4, but becomes a world-beater from f2 onwards. I can't say how well it performs at a half-stop between f1.4 and f2 (I don't possess a 50/1.4 for appraisal), but personally I'd operate at f2 anyway, in even low-light conditions. At f2, it really stands out as head and shoulders sharper than anything else (mind you, at f2.8 it's even better!).

I don't think a hood will make much difference - it'll improve contrast in certain situations, but the basic lens resolution will of course remain unaffected.

paperbag846 · 03-29-2011, 11:11 PM

Originally posted by m42man

I don't think a hood will make much difference - it'll improve contrast in certain situations, but the basic lens resolution will of course remain unaffected.

I used to think that. I was wrong. Indoors or out, this lens' microcontrast is greatly affected by the lack of a hood, with looks like softness.

If you aren't using a good hood with this 50mm you aren't really trying it.

m42man · 03-29-2011, 11:20 PM

Originally posted by paperbag846

I used to think that. I was wrong. Indoors or out, this lens' microcontrast is greatly affected by the lack of a hood, with looks like softness.

If you aren't using a good hood with this 50mm you aren't really trying it.

I see - OK, I stand corrected!

I shall make a point of using a hood with my 50s (and other vintage lenses) in future...

paperbag846 · 03-29-2011, 11:29 PM

Yes, hoods are really necessary with all lenses, but the 50 1.4 is particularly susceptible to flares.

The real problem is people comparing the 1.7 with the 1.4. The 1.7 has a recessed front element. It's like a little built in hood. With the 1.4, the front element is pretty much completely exposed. If you shoot both with no hood, you will think the 1.4 is soft.

timo · 03-30-2011, 02:20 AM

Originally posted by paperbag846

Yes, hoods are really necessary with all lenses, but the 50 1.4 is particularly susceptible to flares.

The real problem is people comparing the 1.7 with the 1.4. The 1.7 has a recessed front element. It's like a little built in hood. With the 1.4, the front element is pretty much completely exposed. If you shoot both with no hood, you will think the 1.4 is soft.

Actually I do think the 1.4 has less contrast wide open than the 1.7 even in conditions where a hood would be unnecessary, like indoors in natural light, but you can easily address that in PP. I sold the FA50 1.4, and have the FA50 1.7. I think the 1.4 was slightly better generally (better nearer the edges), but honestly the difference is so slight as not to matter. With both, accurate focus wide open is much more a factor than the qualities of the lens.

bdery · 03-30-2011, 04:59 AM

Originally posted by paperbag846

Yes, hoods are really necessary with all lenses

No, but that's beside the point of this thread.

I personally stepped up from the M50 f2 to the A50 f1,4 to the F50 f1,7 and I consider that I have upgraded my IQ at each step.

The bokeh of the f1,4 lenses is slightly better (though not much) but the sharpness of the f1,7 is the best, only equalled by the DA21 and bested by the FA50 macro (in my lineup).

Since I use the f1,7 for low light, bokeh is not my main concern, getting enough light in is. And I was never comfortable shooting wide open with my f1,4, so I'd rather have a sharp f1,7 than a soft f1,4 (wide open, again).

mikem · 03-30-2011, 01:36 PM

I used to have the A 50mm but I never used it because I'm terrible at MF, especially when I'm using the lens in low light. I now have an F 50mm f/1.7 and the AF makes a world of difference for me. I picked up a gently loved copy for about $100.

03-29-2011, 04:20 PM	#1
tim_kayak New Member Join Date: Mar 2011 Location: London Posts: 8	Penta-F/FA 50mm f/1.7 and FA 50mm f/1.4 I'm thinking of upgrading my Pentax-A 50mm to an af version. The thing I'd like to know is weather af would be a worthwhile upgrade for me. I bought the lens to use in very low light in a temporary night club and don’t know if an af lens would increase the accuracy of my focusing (I use the 'beep' anyway). Some examples of pic taken with my 'A' lens in very low light can be seen here Xsport International I particularly had problems taken pics of people in focus. My other question is how comparable are the F/Fa 1.7 and FA 1.4 'like for like' (ie at 1.7 up)? one reviewer has said that the softness of the 1.4 can be fixed with a hood, anyone else had this experience too?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
For Sale - Sold: SMC Takumar 50mm 1.4 / Pentax-A 50mm 1.7 / Pentax-M 50mm 1.4 (US)	JP_Seattle	Sold Items	3	09-02-2010 06:17 PM
For Sale - Sold: Penta-F 50mm f1.7 (Worldwide)	cps_goodbuy	Sold Items	8	04-17-2010 12:08 PM
For Sale - Sold: F 24-50mm 4, A 24-50mm 4, M 35mm 2, M 50mm 1.4, A 35-105mm 3.5, A 70-210mm 4	raybird	Sold Items	7	08-29-2008 01:06 PM
penta 16-50mm lens alternative	vincentgargano	Pentax SLR Lens Discussion	12	05-05-2008 02:10 PM

03-29-2011, 04:22 PM	#2
paperbag846 Veteran Member Join Date: Jul 2010 Photos: Gallery Posts: 2,395	Yes, it can be fixed with a hood. However, at f1.7, the 50mm 1.7 lens is sharper than the 1.4 lens at 1.7. The 50mm 1.7 is the best lens for sharp photos in the lowest light IMHO. AF will help you if you use center point focus and focus on something bright (a shiny table reflecting light, etc). But you will have to manually focus too, sometimes.

03-29-2011, 11:05 PM	#3
m42man Veteran Member Join Date: Jan 2010 Location: Southern England Posts: 624	Here's a useful comparison of the two lenses (and several others): Nifty 50 Shootout on Pentax K-7 (updated 1/22) ERPhotoReview You'll see here that the 50/1.4 is surprisingly soft at f1.4, but becomes a world-beater from f2 onwards. I can't say how well it performs at a half-stop between f1.4 and f2 (I don't possess a 50/1.4 for appraisal), but personally I'd operate at f2 anyway, in even low-light conditions. At f2, it really stands out as head and shoulders sharper than anything else (mind you, at f2.8 it's even better!). I don't think a hood will make much difference - it'll improve contrast in certain situations, but the basic lens resolution will of course remain unaffected.

03-29-2011, 11:11 PM	#4
paperbag846 Veteran Member Join Date: Jul 2010 Photos: Gallery Posts: 2,395	Originally posted by m42man I don't think a hood will make much difference - it'll improve contrast in certain situations, but the basic lens resolution will of course remain unaffected. I used to think that. I was wrong. Indoors or out, this lens' microcontrast is greatly affected by the lack of a hood, with looks like softness. If you aren't using a good hood with this 50mm you aren't really trying it.

03-29-2011, 11:20 PM	#5
m42man Veteran Member Join Date: Jan 2010 Location: Southern England Posts: 624	Originally posted by paperbag846 I used to think that. I was wrong. Indoors or out, this lens' microcontrast is greatly affected by the lack of a hood, with looks like softness. If you aren't using a good hood with this 50mm you aren't really trying it. I see - OK, I stand corrected! I shall make a point of using a hood with my 50s (and other vintage lenses) in future...

03-29-2011, 11:29 PM	#6
paperbag846 Veteran Member Join Date: Jul 2010 Photos: Gallery Posts: 2,395	Yes, hoods are really necessary with all lenses, but the 50 1.4 is particularly susceptible to flares. The real problem is people comparing the 1.7 with the 1.4. The 1.7 has a recessed front element. It's like a little built in hood. With the 1.4, the front element is pretty much completely exposed. If you shoot both with no hood, you will think the 1.4 is soft.

03-30-2011, 02:20 AM	#7
timo Veteran Member Join Date: Nov 2006 Location: former Arsenal football stadium Photos: Gallery Posts: 431	Originally posted by paperbag846 Yes, hoods are really necessary with all lenses, but the 50 1.4 is particularly susceptible to flares. The real problem is people comparing the 1.7 with the 1.4. The 1.7 has a recessed front element. It's like a little built in hood. With the 1.4, the front element is pretty much completely exposed. If you shoot both with no hood, you will think the 1.4 is soft. Actually I do think the 1.4 has less contrast wide open than the 1.7 even in conditions where a hood would be unnecessary, like indoors in natural light, but you can easily address that in PP. I sold the FA50 1.4, and have the FA50 1.7. I think the 1.4 was slightly better generally (better nearer the edges), but honestly the difference is so slight as not to matter. With both, accurate focus wide open is much more a factor than the qualities of the lens.

03-30-2011, 04:59 AM	#8
bdery Pentaxian Join Date: Mar 2008 Location: Quebec city, Canada Photos: Gallery Posts: 9,362	Originally posted by paperbag846 Yes, hoods are really necessary with all lenses No, but that's beside the point of this thread. I personally stepped up from the M50 f2 to the A50 f1,4 to the F50 f1,7 and I consider that I have upgraded my IQ at each step. The bokeh of the f1,4 lenses is slightly better (though not much) but the sharpness of the f1,7 is the best, only equalled by the DA21 and bested by the FA50 macro (in my lineup). Since I use the f1,7 for low light, bokeh is not my main concern, getting enough light in is. And I was never comfortable shooting wide open with my f1,4, so I'd rather have a sharp f1,7 than a soft f1,4 (wide open, again).

03-30-2011, 01:36 PM	#9
mikem Senior Member Join Date: Mar 2008 Posts: 101	I used to have the A 50mm but I never used it because I'm terrible at MF, especially when I'm using the lens in low light. I now have an F 50mm f/1.7 and the AF makes a world of difference for me. I picked up a gently loved copy for about $100.