Which 50 to keep? Da vs F 1.7

skierd · 04-03-2015, 09:08 PM

After not wanting a 50 at all, I've been using a DA 50mm f1.8 for a portrait class and its a nice little lens. Yesterday I picked up a F 50mm f1.7 for a song locally with the intent to resell it... But which to sell? I don't need both, and with a DA 40mm limited and a desire for a DA70ltd in the future (which I could almost afford by selling both 50's) I wonder if either 50 is necessary at all?

WWPFD?

Stavri · 04-03-2015, 09:12 PM

Sell the F 50/f1.7 to me for a rhyme and a sonnet...

The F 50/1.7 is identical the to M/A 50/f1.7 one of the best normal primes...(I make no secret of being a fan of the F series) It's better built than the DA, (has more CA) I speculate since the front element is somewhat "flatter" than that of the DA it should be sharper edge to edge. Although they're similarly spec'ed expect a 2/3 stop brighter images with the F 50/1.7 and those warm bright vintage Pentax colors....

stevebrot · 04-03-2015, 09:36 PM

Originally posted by Stavri

Although they're similarly spec'ed expect a 2/3 stop brighter images with the F 50/1.7 and those warm bright vintage Pentax colors....

2/3 stop brighter? The F 50/1.7 is only 1/4 stop faster full open and stopped down should transmit about the same light for a given aperture setting. Is there a secret fault to the DA 50/1.8 that sucks light? I don't have the F 50, but I do have the optically identical M and A versions as well as the DA 50. I will have to test this out.

Steve

fuent104 · 04-03-2015, 10:17 PM

Originally posted by skierd

After not wanting a 50 at all, I've been using a DA 50mm f1.8 for a portrait class and its a nice little lens. Yesterday I picked up a F 50mm f1.7 for a song locally with the intent to resell it... But which to sell? I don't need both, and with a DA 40mm limited and a desire for a DA70ltd in the future (which I could almost afford by selling both 50's) I wonder if either 50 is necessary at all?

WWPFD?

It's not necessary unless you feel like it is. Which it does not sound like. A 40mm and 70mm is a more versatile combo than a 40mm and a 50mm.

**ismaelg** · 04-04-2015, 03:24 AM

Get a second body and keep both. Fast 50's are sacred, you know?

My F50/1.7 is my favorite lens. I haven´t tried the 1.8 but they should be close. In terms of performance, sample variation may be a key here. Test both side by side at wide open, f2 and so on and check if one is noticeably better than the other in terms of center sharpness, corners, CA etc.
Another factor is size, weight, looks and feel. That's very subjective and only you can determine how important and which you like better.
Now, the 40/70 idea sounds like a killer combo as well.......

Thanks,

aurele · 04-04-2015, 04:22 AM

Originally posted by skierd

After not wanting a 50 at all, I've been using a DA 50mm f1.8 for a portrait class and its a nice little lens. Yesterday I picked up a F 50mm f1.7 for a song locally with the intent to resell it... But which to sell?

Both lens use the same optical formula (6 elements in 5 groups). So results should be pretty much the same.

My advise : Keep the F if you are going to use film body, otherwise sell it.

carpents · 04-04-2015, 06:07 AM

They're both very good lenses. The DA 50/1.8 has lower chromatic aberration and is a touch sharper in the corners, so if purely image quality is all you're after, sell the F.

Na Horuk · 04-04-2015, 06:52 AM

Nothing wrong with the older 50mm. The main draw to the DA 50mm is that you get a brand new lens with modern lens coatings and warranty for.. well, less money than the older, used FA or F series lenses. But other that, the FA and F have more features. Now, optically they might not be any better, but they have distance scales, aperture ring, maybe they come with a lens hood, they have a metal mount and more metal in the actual body of the lens.. Difficult to say which one. Id say look at what is actually available on the used market, maybe you get a good deal. Or look at photos of those lenses and get the one that catches your eye. Or just buy according to least resistance, and get DA 50mm and never look back.
I dont think any of these lenses will disappoint you optically. But think of the features. If you want to use macro bellows or tubes, if you want to use the lens on an older film camera, then you need aperture ring.

Edit: Oh, and yeah, why get rid of one? I have a couple 50mm lenses. Some people have dozens. No problem there, as long a you use them. Sell the one that you use the least, or the one that you can get the most money for (if there is no real advantage)

dakight · 04-04-2015, 07:12 AM

I have 3 50's... count 'em the DA 50 f1.8, the M 50 f1.7 , and the A 50 f2.0. Do I "need" 3? Well, no I don't; am I going to keep all three? You betcha I am!

skierd · 04-04-2015, 09:10 AM

I've got 3 as well, the A 50 f2, the F, and the DA. Also have a takumar 55 f1.8 with adapter.

The F came attached to a good zx-7, so the aperture ring isn't important.

stevebrot · 04-04-2015, 06:03 PM - **1 Like**

Originally posted by aurele

Both lens use the same optical formula (6 elements in 5 groups). So results should be pretty much the same.

The designs are similar, though not the quite the same. As carpents noted, the two lenses have different image characteristics.

Steve

aurele · 04-05-2015, 12:36 AM

Originally posted by stevebrot

The designs are similar, though not the quite the same. As carpents noted, the two lenses have different image characteristics.

Steve

i guess, it's due to the coating, because according to Pentax spec' sheet, both lenses use strictly the same 6/5 design.

Na Horuk · 04-05-2015, 03:56 AM

Yeah, I think M 50mm f1.7 all the way to DA 50mm f1.8 have the same optical design. Now, this doesn't mean its the exact same lens. For example, regulations on materials change over time, factories and machining technologies change, employees and workers change, and finally lens coatings change as well. So I do believe when people say the DA has the best flare resistance, and the F is the sharpest (but loudest AF). And they might even have different contrast and slightly different bokeh. But the differences between them will be much smaller than in comparison with.. lets say Sigma 50mm f1.4 or Industar 50-2 (f3.5)

Keep in mind that even something as little as changing metal straight aperture blades for plastic rounded aperture blades will affect the image, in terms of bokeh, starbursts, contrast.. and I think the DA 50mm has rounded aperture blades, right? I know my M 50mm f1.7 would produce quite different bokeh because of its aperture shape:

Cosmic fly sitting on a tree - Pentax M 50mm f1.7, around f2, f2,8. Dark conditions, very high ISO

The above photo would have a very different look if the lens had rounded aperture blades. Those OoF star-like hexagons would be round.

**boriscleto** · 04-05-2015, 05:36 AM - **1 Like**

Originally posted by dakight

I have 3 50's... count 'em the DA 50 f1.8, the M 50 f1.7 , and the A 50 f2.0. Do I "need" 3? Well, no I don't; am I going to keep all three? You betcha I am!

Originally posted by skierd

I've got 3 as well, the A 50 f2, the F, and the DA. Also have a takumar 55 f1.8 with adapter.

The F came attached to a good zx-7, so the aperture ring isn't important.

Only 3? I'm up to 22...in 5 different lens mounts...

carpents · 04-05-2015, 06:09 AM - **1 Like**

Originally posted by aurele

i guess, it's due to the coating, because according to Pentax spec' sheet, both lenses use strictly the same 6/5 design.

Whatever the cause, they are quite noticeably different.

We (PentaxForums) are currently writing an in-depth comparison article between the DA50/1.8 and the M50/1.7 and two other 50mm lenses. They're all very good, but the modern DA is without question the best for corner sharpness and CA. If that matters to you, then the DA is 'better'.

04-03-2015, 09:08 PM	#1
skierd Veteran Member Join Date: Mar 2011 Location: Fairbanks, AK Photos: Gallery Posts: 1,472	Which 50 to keep? Da vs F 1.7 After not wanting a 50 at all, I've been using a DA 50mm f1.8 for a portrait class and its a nice little lens. Yesterday I picked up a F 50mm f1.7 for a song locally with the intent to resell it... But which to sell? I don't need both, and with a DA 40mm limited and a desire for a DA70ltd in the future (which I could almost afford by selling both 50's) I wonder if either 50 is necessary at all? WWPFD?

04-03-2015, 09:12 PM	#2
Stavri Veteran Member Join Date: Aug 2014 Location: at a Bean & Leaf Photos: Albums Posts: 1,832	Sell the F 50/f1.7 to me for a rhyme and a sonnet... The F 50/1.7 is identical the to M/A 50/f1.7 one of the best normal primes...(I make no secret of being a fan of the F series) It's better built than the DA, (has more CA) I speculate since the front element is somewhat "flatter" than that of the DA it should be sharper edge to edge. Although they're similarly spec'ed expect a 2/3 stop brighter images with the F 50/1.7 and those warm bright vintage Pentax colors.... Last edited by Stavri; 04-03-2015 at 09:21 PM.

04-04-2015, 06:52 AM	#8
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	Nothing wrong with the older 50mm. The main draw to the DA 50mm is that you get a brand new lens with modern lens coatings and warranty for.. well, less money than the older, used FA or F series lenses. But other that, the FA and F have more features. Now, optically they might not be any better, but they have distance scales, aperture ring, maybe they come with a lens hood, they have a metal mount and more metal in the actual body of the lens.. Difficult to say which one. Id say look at what is actually available on the used market, maybe you get a good deal. Or look at photos of those lenses and get the one that catches your eye. Or just buy according to least resistance, and get DA 50mm and never look back. I dont think any of these lenses will disappoint you optically. But think of the features. If you want to use macro bellows or tubes, if you want to use the lens on an older film camera, then you need aperture ring. Edit: Oh, and yeah, why get rid of one? I have a couple 50mm lenses. Some people have dozens. No problem there, as long a you use them. Sell the one that you use the least, or the one that you can get the most money for (if there is no real advantage) Last edited by Na Horuk; 04-04-2015 at 07:15 AM.

04-05-2015, 03:56 AM	#13
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	Yeah, I think M 50mm f1.7 all the way to DA 50mm f1.8 have the same optical design. Now, this doesn't mean its the exact same lens. For example, regulations on materials change over time, factories and machining technologies change, employees and workers change, and finally lens coatings change as well. So I do believe when people say the DA has the best flare resistance, and the F is the sharpest (but loudest AF). And they might even have different contrast and slightly different bokeh. But the differences between them will be much smaller than in comparison with.. lets say Sigma 50mm f1.4 or Industar 50-2 (f3.5) Keep in mind that even something as little as changing metal straight aperture blades for plastic rounded aperture blades will affect the image, in terms of bokeh, starbursts, contrast.. and I think the DA 50mm has rounded aperture blades, right? I know my M 50mm f1.7 would produce quite different bokeh because of its aperture shape: Cosmic fly sitting on a tree - Pentax M 50mm f1.7, around f2, f2,8. Dark conditions, very high ISO The above photo would have a very different look if the lens had rounded aperture blades. Those OoF star-like hexagons would be round. Last edited by Na Horuk; 04-05-2015 at 05:46 AM.

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04-03-2015, 09:36 PM	#3
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Stavri Although they're similarly spec'ed expect a 2/3 stop brighter images with the F 50/1.7 and those warm bright vintage Pentax colors.... 2/3 stop brighter? The F 50/1.7 is only 1/4 stop faster full open and stopped down should transmit about the same light for a given aperture setting. Is there a secret fault to the DA 50/1.8 that sucks light? I don't have the F 50, but I do have the optically identical M and A versions as well as the DA 50. I will have to test this out. Steve

04-03-2015, 10:17 PM	#4
fuent104 Veteran Member Join Date: Apr 2011 Location: California Photos: Gallery Posts: 1,356	Originally posted by skierd After not wanting a 50 at all, I've been using a DA 50mm f1.8 for a portrait class and its a nice little lens. Yesterday I picked up a F 50mm f1.7 for a song locally with the intent to resell it... But which to sell? I don't need both, and with a DA 40mm limited and a desire for a DA70ltd in the future (which I could almost afford by selling both 50's) I wonder if either 50 is necessary at all? WWPFD? It's not necessary unless you feel like it is. Which it does not sound like. A 40mm and 70mm is a more versatile combo than a 40mm and a 50mm.

04-04-2015, 03:24 AM	#5
ismaelg Loyal Site Supporter Join Date: Apr 2009 Location: Puerto Rico Photos: Gallery Posts: 2,681	Get a second body and keep both. Fast 50's are sacred, you know? My F50/1.7 is my favorite lens. I haven´t tried the 1.8 but they should be close. In terms of performance, sample variation may be a key here. Test both side by side at wide open, f2 and so on and check if one is noticeably better than the other in terms of center sharpness, corners, CA etc. Another factor is size, weight, looks and feel. That's very subjective and only you can determine how important and which you like better. Now, the 40/70 idea sounds like a killer combo as well....... Thanks,

04-04-2015, 04:22 AM	#6
aurele Veteran Member Join Date: Jan 2011 Location: Paris, France Photos: Albums Posts: 3,217	Originally posted by skierd After not wanting a 50 at all, I've been using a DA 50mm f1.8 for a portrait class and its a nice little lens. Yesterday I picked up a F 50mm f1.7 for a song locally with the intent to resell it... But which to sell? Both lens use the same optical formula (6 elements in 5 groups). So results should be pretty much the same. My advise : Keep the F if you are going to use film body, otherwise sell it.

04-04-2015, 06:07 AM	#7
carpents Veteran Member Join Date: Sep 2006 Location: West Chester, PA Photos: Gallery \| Albums Posts: 1,420	They're both very good lenses. The DA 50/1.8 has lower chromatic aberration and is a touch sharper in the corners, so if purely image quality is all you're after, sell the F.

04-04-2015, 07:12 AM	#9
dakight Veteran Member Join Date: Sep 2014 Location: Phoenix, AZ Photos: Albums Posts: 1,216	I have 3 50's... count 'em the DA 50 f1.8, the M 50 f1.7 , and the A 50 f2.0. Do I "need" 3? Well, no I don't; am I going to keep all three? You betcha I am!

04-04-2015, 09:10 AM	#10
skierd Veteran Member Join Date: Mar 2011 Location: Fairbanks, AK Photos: Gallery Posts: 1,472 Original Poster	I've got 3 as well, the A 50 f2, the F, and the DA. Also have a takumar 55 f1.8 with adapter. The F came attached to a good zx-7, so the aperture ring isn't important.

04-04-2015, 06:03 PM - 1 Like	#11
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by aurele Both lens use the same optical formula (6 elements in 5 groups). So results should be pretty much the same. The designs are similar, though not the quite the same. As carpents noted, the two lenses have different image characteristics. Steve

04-05-2015, 12:36 AM	#12
aurele Veteran Member Join Date: Jan 2011 Location: Paris, France Photos: Albums Posts: 3,217	Originally posted by stevebrot The designs are similar, though not the quite the same. As carpents noted, the two lenses have different image characteristics. Steve i guess, it's due to the coating, because according to Pentax spec' sheet, both lenses use strictly the same 6/5 design.

04-05-2015, 05:36 AM - 1 Like	#14
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,475	Originally posted by dakight I have 3 50's... count 'em the DA 50 f1.8, the M 50 f1.7 , and the A 50 f2.0. Do I "need" 3? Well, no I don't; am I going to keep all three? You betcha I am! Originally posted by skierd I've got 3 as well, the A 50 f2, the F, and the DA. Also have a takumar 55 f1.8 with adapter. The F came attached to a good zx-7, so the aperture ring isn't important. Only 3? I'm up to 22...in 5 different lens mounts...

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04-05-2015, 06:09 AM - 1 Like	#15
carpents Veteran Member Join Date: Sep 2006 Location: West Chester, PA Photos: Gallery \| Albums Posts: 1,420	Originally posted by aurele i guess, it's due to the coating, because according to Pentax spec' sheet, both lenses use strictly the same 6/5 design. Whatever the cause, they are quite noticeably different. We (PentaxForums) are currently writing an in-depth comparison article between the DA50/1.8 and the M50/1.7 and two other 50mm lenses. They're all very good, but the modern DA is without question the best for corner sharpness and CA. If that matters to you, then the DA is 'better'.