RE: "Why I love the Pentax 50mm f1.4" thread

pjsnell · 08-26-2008, 12:39 PM

I have a DA40, and although I like it a lot, it isn't what I'd consider "fast". The examples from this thread have me thinking that this lens is the fast 50 I've been looking for.

For those of you who have both, how do they compare?

My thoughts right now are to get the FA50, and sell the DA40 and go for a wider limited lens.

axl · 08-26-2008, 02:02 PM

Keep DA40 and go for older manual version of fast 50. Something like M50 f1.7... apparently the 1.7 ones are sharper then 1.4s between f2 and f2.8...
just my 2p
BR

GSk · 08-26-2008, 02:10 PM

I have both.

I now use the 40mm a lot, but the 50mm is barely in use. The reason for that is because the 40mm is sharp to the edges from f2.8, and the 50mm is not sharp enough for my taste below f2.8.

k100d · 08-26-2008, 02:13 PM

how bad do you need the speed?

pjsnell · 08-27-2008, 08:38 AM

My main subject is a three year old, so I need "Ludicrous speed".

séamuis · 08-27-2008, 08:49 AM

Originally posted by pjsnell

My main subject is a three year old, so I need "Ludicrous speed".

how would the FA 50 1.4 help in this respect? at 1.4 the DOF would be so thin that it would be very difficult even with AF to obtain accurate focus. and you would likely be stopping it down to 2 or 2.8 to obtain overall sharpness and slightly larger DOF anyway, there by making the DA40 just as good. I rarely use my 50mm 1.7 at 1.7 it normally gets used at anywhere between 2 and 8 and I have taken my share of children photos. (and mind you this is a manual lens). unless you are going to be taking generally most or all of your photos in very low light I fail to see why the DA40 and maybe a slightly higher ISO cant yield just as good results. of course the difference in FOV is a whole different situation.

**madmikess** · 08-27-2008, 09:12 AM

Originally posted by pjsnell

My main subject is a three year old, so I need "Ludicrous speed".

Do you get a faint hint of plaid at that speed?

pjsnell · 08-27-2008, 09:14 AM

Originally posted by séamuis

how would the FA 50 1.4 help in this respect? at 1.4 the DOF would be so thin that it would be very difficult even with AF to obtain accurate focus. and you would likely be stopping it down to 2 or 2.8 to obtain overall sharpness and slightly larger DOF anyway, there by making the DA40 just as good. I rarely use my 50mm 1.7 at 1.7 it normally gets used at anywhere between 2 and 8 and I have taken my share children photos. (and mind you this is a manual lens). unless you are going to be taking generally most or all of your photos in very low light I fail to see why the DA40 and mighby a slightly higher ISO cant yeild just as good results. of course the difference in FOV is a whole different situation.

Excellent argument.

pjsnell · 08-27-2008, 09:15 AM

Originally posted by madmikess

Do you get a faint hint of plaid at that speed?

yeah purple fringed.

**madmikess** · 08-27-2008, 09:18 AM

I know the feeling though, I have a 5yr, 3yr, and 10 month old... It's hard to get them all in once place at the same time..

pjsnell · 08-27-2008, 09:21 AM

Add my relative photographic ineptitude to the mix...

It's a classic case of picture envy.

**madmikess** · 08-27-2008, 09:32 AM

I know that all too well also.

I'm trying, but I generally always take my pictures in auto mode.

Marc Sabatella · 08-27-2008, 11:00 AM

I have the DA40 and an A50/1.7. the DA40 gets way more use, because it is a better focal length for me and is so wonderfully compact and light and focuses *very* fast. It's "fast enough" indoors for relatively stationary subjects - eg, most of the time there is enough light for 1/20" at ISO 1600. I do use my 50 when the light is even lower, especially if I can be a bit further from my If I really need to freeze motion, my MF 50 isn't going to cut it. First, because I can't focus that fast, second, because it's only a stop and a half faster and that's still not going to get me over 1/100, and third, because it DOF is so shallow it's hard to get an entire object in focus, and more so if its motion carries it in and out of the focal plane. And AF lens would solve #1 and help a little toward #2, but not address #3.

Realistically, if you're trying to stop motion in low light, you really want flash.

pjsnell · 08-27-2008, 11:34 AM

Originally posted by Marc Sabatella

I have the DA40 and an A50/1.7. the DA40 gets way more use, because it is a better focal length for me and is so wonderfully compact and light and focuses *very* fast. It's "fast enough" indoors for relatively stationary subjects - eg, most of the time there is enough light for 1/20" at ISO 1600. I do use my 50 when the light is even lower, especially if I can be a bit further from my If I really need to freeze motion, my MF 50 isn't going to cut it. First, because I can't focus that fast, second, because it's only a stop and a half faster and that's still not going to get me over 1/100, and third, because it DOF is so shallow it's hard to get an entire object in focus, and more so if its motion carries it in and out of the focal plane. And AF lens would solve #1 and help a little toward #2, but not address #3.

Realistically, if you're trying to stop motion in low light, you really want flash.

My use of the word "fast" is misleading. I meant like "fast fifty lens", which on second thought (and after everyone's comments) the DA40 qualifies as (although it's 10mm shorter).

I don't bother trying to catch the monster in motion indoors, although a strobe would be helpful. I would like to be able to accomplish some portraits of her that are of the quality of some of the ones posted in the original FA50 love-in thread. I'd be happy with half as good, as the 3rd one vizjerei posted. Photos like that would make me a hero in my house (for a little while atleast).

Marc Sabatella · 08-27-2008, 01:38 PM

Originally posted by pjsnell

My use of the word "fast" is misleading. I meant like "fast fifty lens", which on second thought (and after everyone's comments) the DA40 qualifies as (although it's 10mm shorter).

Right. I did realize by "fast" you meant the shutter speed that results from large maximum aperture, not AF speed, but I assumed that since you mentioned that the DA40 wasn't fast enough, and specifically mentioned toddlers, that you were looking for motion-stopping shutter speeds, not just hand-holdable shutter speeds.

If you can get the kid to sit still, I would think f/2.8 *should* be "fast" enough, although perhaps you really want the shallower DOF for these kind of portaits, and the ability to not necessarily have to max the ISO. And indeed, the longer focal length of the 50 as well as the wider maximum aperture both help. It's also a just plain better focal length for portraits. So, no doubt in my mind that you want a 50.

Personally, I'd keep the DA40 and go cheap on the 50 (I just picked up an M50/1.7 for $33 on Ebay - this *is* still easy to find for cheap). But selling the 40 and going with a 35/50 pair is a fine idea too, especially if you often feel the DA40 is either just a little *too* tight or not tight enough.

08-27-2008, 08:49 AM	#6
séamuis Banned Join Date: Oct 2007 Location: Savannah, U.S./Baguio City, P.H. Posts: 5,979	Originally posted by pjsnell My main subject is a three year old, so I need "Ludicrous speed". how would the FA 50 1.4 help in this respect? at 1.4 the DOF would be so thin that it would be very difficult even with AF to obtain accurate focus. and you would likely be stopping it down to 2 or 2.8 to obtain overall sharpness and slightly larger DOF anyway, there by making the DA40 just as good. I rarely use my 50mm 1.7 at 1.7 it normally gets used at anywhere between 2 and 8 and I have taken my share of children photos. (and mind you this is a manual lens). unless you are going to be taking generally most or all of your photos in very low light I fail to see why the DA40 and maybe a slightly higher ISO cant yield just as good results. of course the difference in FOV is a whole different situation. Last edited by séamuis; 08-27-2008 at 09:28 AM.

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08-26-2008, 12:39 PM	#1
pjsnell Inactive Account Join Date: Jul 2008 Location: Ontario, Canada Posts: 16	RE: "Why I love the Pentax 50mm f1.4" thread I have a DA40, and although I like it a lot, it isn't what I'd consider "fast". The examples from this thread have me thinking that this lens is the fast 50 I've been looking for. For those of you who have both, how do they compare? My thoughts right now are to get the FA50, and sell the DA40 and go for a wider limited lens.

08-26-2008, 02:02 PM	#2
axl Veteran Member Join Date: Mar 2007 Location: Nove Zamky, Slovakia Photos: Gallery \| Albums Posts: 7,183	Keep DA40 and go for older manual version of fast 50. Something like M50 f1.7... apparently the 1.7 ones are sharper then 1.4s between f2 and f2.8... just my 2p BR

08-26-2008, 02:10 PM	#3
GSk Inactive Account Join Date: Jan 2008 Location: Sørumsand, Norway Photos: Gallery \| Albums Posts: 59	I have both. I now use the 40mm a lot, but the 50mm is barely in use. The reason for that is because the 40mm is sharp to the edges from f2.8, and the 50mm is not sharp enough for my taste below f2.8.

08-26-2008, 02:13 PM	#4
k100d Veteran Member Join Date: Feb 2008 Location: Toronto Posts: 3,911	how bad do you need the speed?

08-27-2008, 08:38 AM	#5
pjsnell Inactive Account Join Date: Jul 2008 Location: Ontario, Canada Posts: 16 Original Poster	My main subject is a three year old, so I need "Ludicrous speed".

08-27-2008, 09:12 AM	#7
madmikess Site Supporter Join Date: Aug 2008 Location: Kenmore, NY Photos: Gallery \| Albums Posts: 482	Originally posted by pjsnell My main subject is a three year old, so I need "Ludicrous speed". Do you get a faint hint of plaid at that speed?

08-27-2008, 09:14 AM	#8
pjsnell Inactive Account Join Date: Jul 2008 Location: Ontario, Canada Posts: 16 Original Poster	Originally posted by séamuis how would the FA 50 1.4 help in this respect? at 1.4 the DOF would be so thin that it would be very difficult even with AF to obtain accurate focus. and you would likely be stopping it down to 2 or 2.8 to obtain overall sharpness and slightly larger DOF anyway, there by making the DA40 just as good. I rarely use my 50mm 1.7 at 1.7 it normally gets used at anywhere between 2 and 8 and I have taken my share children photos. (and mind you this is a manual lens). unless you are going to be taking generally most or all of your photos in very low light I fail to see why the DA40 and mighby a slightly higher ISO cant yeild just as good results. of course the difference in FOV is a whole different situation. Excellent argument.

08-27-2008, 09:15 AM	#9
pjsnell Inactive Account Join Date: Jul 2008 Location: Ontario, Canada Posts: 16 Original Poster	Originally posted by madmikess Do you get a faint hint of plaid at that speed? yeah purple fringed.

08-27-2008, 09:18 AM	#10
madmikess Site Supporter Join Date: Aug 2008 Location: Kenmore, NY Photos: Gallery \| Albums Posts: 482	I know the feeling though, I have a 5yr, 3yr, and 10 month old... It's hard to get them all in once place at the same time..

08-27-2008, 09:21 AM	#11
pjsnell Inactive Account Join Date: Jul 2008 Location: Ontario, Canada Posts: 16 Original Poster	Add my relative photographic ineptitude to the mix... It's a classic case of picture envy.

08-27-2008, 09:32 AM	#12
madmikess Site Supporter Join Date: Aug 2008 Location: Kenmore, NY Photos: Gallery \| Albums Posts: 482	I know that all too well also. I'm trying, but I generally always take my pictures in auto mode.

08-27-2008, 11:00 AM	#13
Marc Sabatella Veteran Member Join Date: Sep 2006 Location: Denver, CO Photos: Gallery Posts: 10,685	I have the DA40 and an A50/1.7. the DA40 gets way more use, because it is a better focal length for me and is so wonderfully compact and light and focuses very fast. It's "fast enough" indoors for relatively stationary subjects - eg, most of the time there is enough light for 1/20" at ISO 1600. I do use my 50 when the light is even lower, especially if I can be a bit further from my If I really need to freeze motion, my MF 50 isn't going to cut it. First, because I can't focus that fast, second, because it's only a stop and a half faster and that's still not going to get me over 1/100, and third, because it DOF is so shallow it's hard to get an entire object in focus, and more so if its motion carries it in and out of the focal plane. And AF lens would solve #1 and help a little toward #2, but not address #3. Realistically, if you're trying to stop motion in low light, you really want flash.

08-27-2008, 11:34 AM	#14
pjsnell Inactive Account Join Date: Jul 2008 Location: Ontario, Canada Posts: 16 Original Poster	Originally posted by Marc Sabatella I have the DA40 and an A50/1.7. the DA40 gets way more use, because it is a better focal length for me and is so wonderfully compact and light and focuses very fast. It's "fast enough" indoors for relatively stationary subjects - eg, most of the time there is enough light for 1/20" at ISO 1600. I do use my 50 when the light is even lower, especially if I can be a bit further from my If I really need to freeze motion, my MF 50 isn't going to cut it. First, because I can't focus that fast, second, because it's only a stop and a half faster and that's still not going to get me over 1/100, and third, because it DOF is so shallow it's hard to get an entire object in focus, and more so if its motion carries it in and out of the focal plane. And AF lens would solve #1 and help a little toward #2, but not address #3. Realistically, if you're trying to stop motion in low light, you really want flash. My use of the word "fast" is misleading. I meant like "fast fifty lens", which on second thought (and after everyone's comments) the DA40 qualifies as (although it's 10mm shorter). I don't bother trying to catch the monster in motion indoors, although a strobe would be helpful. I would like to be able to accomplish some portraits of her that are of the quality of some of the ones posted in the original FA50 love-in thread. I'd be happy with half as good, as the 3rd one vizjerei posted. Photos like that would make me a hero in my house (for a little while atleast).

08-27-2008, 01:38 PM	#15
Marc Sabatella Veteran Member Join Date: Sep 2006 Location: Denver, CO Photos: Gallery Posts: 10,685	Originally posted by pjsnell My use of the word "fast" is misleading. I meant like "fast fifty lens", which on second thought (and after everyone's comments) the DA40 qualifies as (although it's 10mm shorter). Right. I did realize by "fast" you meant the shutter speed that results from large maximum aperture, not AF speed, but I assumed that since you mentioned that the DA40 wasn't fast enough, and specifically mentioned toddlers, that you were looking for motion-stopping shutter speeds, not just hand-holdable shutter speeds. If you can get the kid to sit still, I would think f/2.8 should be "fast" enough, although perhaps you really want the shallower DOF for these kind of portaits, and the ability to not necessarily have to max the ISO. And indeed, the longer focal length of the 50 as well as the wider maximum aperture both help. It's also a just plain better focal length for portraits. So, no doubt in my mind that you want a 50. Personally, I'd keep the DA40 and go cheap on the 50 (I just picked up an M50/1.7 for $33 on Ebay - this is still easy to find for cheap). But selling the 40 and going with a 35/50 pair is a fine idea too, especially if you often feel the DA40 is either just a little too tight or not tight enough.