M 50 1.7 or F/FA 50 1.7

panicAttack · 03-05-2015, 03:13 PM

Greetings all, and excuse my English.

Unfortunately my sharpest lens I had till today was manual 50 1.7 asashi pentax.

I had some focus ring issues and wanted to repair it and completely messed things up and it cant be repaired anymore.

I used it for full body studio portraits stopped at about f8 and sharpness was great from corner to center. (this is important to me)

Now I want to buy another one, autofocus is great thing but only if the lens is optically the same (or even better) in term of sharpness compared to m 50 1.7.

So, my question is, are autofocus 1.7 lenses F or FA optically same as M 50 1.7 or there are some differences? If they are better that's great.

I have read pentax lens database reviews, M have score of 9.5 (173 reviews), F have 9.7 (73 reviews) and FA 9.8 (26 reviews) but I would like to know if someone had experience with two or even all three of them.

Thank you for your time and patience

**jatrax** · 03-05-2015, 03:19 PM

At f/8 I really do not think you will be able to see any difference.

I like the F 50mm f/1.7 personally but any of them or the FA 50mm f/1.4 or the DA 50mm f/1.8 will look great at f/8

panicAttack · 03-05-2015, 03:30 PM

Originally posted by jatrax

At f/8 I really do not think you will be able to see any difference.

I like the F 50mm f/1.7 personally but any of them or the FA 50mm f/1.4 or the DA 50mm f/1.8 will look great at f/8

thanks for fast reply

I dont use it only at f8, sometimes f2.8 or 5.6, (for headshot portraits) and rarely on 1.7.

but mostly it is on f8 and it(was) so unbelievable sharp.

But I got your point and your are right (only I don't want DA because it is crop lens and dont know about it corner sharpnes, other 1.7 are full frame lenses so when I use it on crop camera I use their best center part)

cheers!

stevebrot · 03-05-2015, 03:52 PM - **1 Like**

Originally posted by panicAttack

are autofocus 1.7 lenses F or FA optically same as M 50 1.7

They are essentially the same optically*, the main differences would be AF (duh), coatings, and build. The M 50/1.7 is a very sturdy and compact lens.

Originally posted by panicAttack

But I got your point and your are right (only I don't want DA because it is crop lens and dont know about it corner sharpnes, other 1.7 are full frame lenses so when I use it on crop camera I use their best center part)

I own the DA 50/1.8 and have shot it on 35mm film. The short answer regarding FF compatibility is that it does vignette more wide open than my other FF fast 50s. This is obvious by direct inspection of the negative for a blank sky shot. Edge sharpness appears to be acceptable, but that is purely anecdotal. Still on my list of things to do is to conduct a head-to-head shoot-out with a few of my favorite 50s (K 55/1.8, M 50/1.7, and KMZ Helios 58/2...might also through in the XR Rikenon just for giggles).

Steve

* Dimitrov's K-mount page uses the same optical diagram for the M, A, F, and FA versions of the 50/1.7

**mwilky55** · 03-05-2015, 04:54 PM

Originally posted by panicAttack

Greetings all, and excuse my English.

Unfortunately my sharpest lens I had till today was manual 50 1.7 asashi pentax.

I had some focus ring issues and wanted to repair it and completely messed things up and it cant be repaired anymore.

I used it for full body studio portraits stopped at about f8 and sharpness was great from corner to center. (this is important to me)

Now I want to buy another one, autofocus is great thing but only if the lens is optically the same (or even better) in term of sharpness compared to m 50 1.7.

So, my question is, are autofocus 1.7 lenses F or FA optically same as M 50 1.7 or there are some differences? If they are better that's great.

I have read pentax lens database reviews, M have score of 9.5 (173 reviews), F have 9.7 (73 reviews) and FA 9.8 (26 reviews) but I would like to know if someone had experience with two or even all three of them.

Thank you for your time and patience

While I haven't done an analysis of sharpness by aperture or anything like that, I really, really like the FA 50 1.7.

Na Horuk · 03-05-2015, 05:27 PM - **1 Like**

Hey, welcome!
M, A, F, FA 50mm f1.7 lenses all follow the same optic design, with relatively small differences (mostly in coatings and shape of aperture blades), so you will not find huge differences in optical quality between them (though, some claim the F series is sharpest). Oh, and the DA 50mm f1.8 fits this as well. The main difference between these lenses is the construction and automation. The M series has no automation at all. It is beloved on these forums because it is a good, sturdy lens for a really low price, even though the prices have risen lately due to its popularity. The A series has auto-aperture, which is a very useful feature! It lets you choose the aperture on the camera body instead of only on the lens' aperture ring. F and FA series allow this as well, but they also have AF! Finally, DA series is full automatic just like the F and FA, but it doesn't even have an aperture ring (which limits its use on older film bodies).

tl:dr; Get A series lens for ease of use. Get F or FA if you want AF. But honestly, the DA 50mm f1.8 is so affordable lately, it might be worth to just go for it. You get the most modern lens coatings, AF, full automation, and warranty. Sure, it is plastic, but it is still durable and much lighter. The amount of force needed to damage the plastic would probably bend or chip the older series lenses as well. I like my M 50mm f1.7, but it is not for the faint of heart. Its for hardcore users, who enjoy an old, metal, manual lens. If this fits you, then go for it

If you get a good copy, any of these lenses will be great. The question is just how much automation you want, and what a good deal you can find.

ChristianRock · 03-05-2015, 07:46 PM

They cost so little, you can get both the M 50 1.7 (for sentimental reasons if anything), and the DA 50 1.8 which will be just as sharp but will render out of focus areas much better than any other 50 due to the rounded blades.

Personally, I am particularly fond of the Sears 50 1.7. It is as sharp as any 50 and pictures just look great.

**clackers** · 03-05-2015, 08:31 PM

Originally posted by ChristianRock

They cost so little, you can get both the M 50 1.7 (for sentimental reasons if anything), and the DA 50 1.8 which will be just as sharp but will render out of focus areas much better than any other 50 due to the rounded blades.

The official comparison on this site found the cheap DA 50 f1.8 did very, very well matched up against the pricey FA f.14 and DFA f2.8 Macro.

Would suit you especially if it's at f8 for your flash portraits or whatever it is you do, panicAttack! :-)

DSims · 03-06-2015, 03:11 AM

The FA43 is going to be your best lens for this application, if it's in your budget.

If not, the A50/1.7 or any of these that have been mentioned should do the job.

I rather like the M50/1.4 I had; its rendering may be a bit different, but it's oddly beautiful: PENTAX : Select a PENTAX interchangeable lens camera or a lens model

panicAttack · 03-06-2015, 03:59 AM

wow guys, thank you all!

I wanted to know if it is the same optical design and got my answer, so I will probably go for FA 50 1.7 there are few selling on ebay right now.

one more thing, I have macro extension rings for my old M 50 1.7

does anyone know if they can fit on FA 50 1.7?

Thanks

Na Horuk · 03-06-2015, 04:37 AM - **1 Like**

The only optical difference between the lenses is lens coatings, which improved over time and reduce flare and ghosting, and aperture blades. Here is a photo showing M 50mm aperture blades:

Cosmic fly

Notice how the OoF highlights are hexagonal, almost like stars? If this same photo were taken with DA 50, they would be almost perfectly round circles. But this only matters when shooting at closed aperture. Wide open (smallest f-number), all lenses produce circles. This photo was around f2.8 I think

Regarding the macro extension tubes.. I think they will work for all Pentax K lenses, but the amount of extra magnification you get depends on a) focal length and b) minimum focus distance of lens. But you might lose things like AF and auto aperture. This is why many people go for the M 50mm: they plan on using it on old film cameras without automation, they plan on using it on bellows or extension tubes, they plan on adapting it to Canon or Sony camera.. For macro you don't need AF anyway, since you are working around the minimum focus distance the whole time anyway

panicAttack · 03-06-2015, 04:49 AM

yes, I don't need autofocus for macro, I used those rings as macro extension or even reverse macro for my M50 1.7 so even if it was autofocus lens, it would be impossible.

FA 50 1.7 and M 50 1.7 have same filter size, so I guess it will be fine.

Thanks again, my choice is FA 50 1.7

It is shame there are no MTF charts for those lenses (or I just cant find them on the internet) to see how they compare with nikon 50 1.8 D or G lenses.

I do have only pentax body and it will be like that for atleast until FF comes, but I see those 2 nikon fifties are so cheap even compared with used pentax autofocus primes on ebay.

Na Horuk · 03-06-2015, 04:58 AM

Nikkor AF Nikkor 50mm f/1.8D on Nikon D7000 versus Nikkor AF-S NIKKOR 50mm f/1.8G on Nikon D7000 versus Pentax smc DA 50mm f1.8 - Side by side lens comparison - DxOMark

This one lets you compare the DA 50mm on K-5 to the Nikon lenses on D7000. Usually you cannot compare data between different cameras/brands, but the K-5 and D7000 both use the same Sony 16MP sensor, with only small difference between them. So you can see the plastic DA 50mm is at least as good, if not better. What I find really great is the DA has much smaller chromatic aberration, good distortion control, high resolution and so on. The resolution of the lenses increases if you choose a K-5IIs (no AA filter) or K-3
Btw, Pentax is also producing the FA 50mm f1.4, which you can buy as new. The f1.4 lenses have a slightly different optical design, though.

panicAttack · 03-06-2015, 05:11 AM

DXOmark generally prefer Nikon stuff (my opinion), so being on par or even better on same sensor is great thing. All three of them are in the same price range here in Croatia.

I compared them on on k-3/d7100 also, and there is small difference in resolution, but overall DA 50 1.8 beats them all.

Now will be great to compare them all with FA 50 1.7 but I am asking too much

Thank you again Na Horuk, you really know how to find things.

yusuf · 03-06-2015, 05:27 AM

Originally posted by Na Horuk

...
If you get a good copy, any of these lenses will be great. The question is just how much automation you want, and what a good deal you can find.

I agree. In fact, you will have hard time differentiating sharpness between all the Pentax fifties (M/A/FA f1.7 or f1.4), marginal if any. The real difference is rendering.

03-05-2015, 03:13 PM	#1
panicAttack Forum Member Join Date: Dec 2013 Posts: 56	M 50 1.7 or F/FA 50 1.7 Greetings all, and excuse my English. Unfortunately my sharpest lens I had till today was manual 50 1.7 asashi pentax. I had some focus ring issues and wanted to repair it and completely messed things up and it cant be repaired anymore. I used it for full body studio portraits stopped at about f8 and sharpness was great from corner to center. (this is important to me) Now I want to buy another one, autofocus is great thing but only if the lens is optically the same (or even better) in term of sharpness compared to m 50 1.7. So, my question is, are autofocus 1.7 lenses F or FA optically same as M 50 1.7 or there are some differences? If they are better that's great. I have read pentax lens database reviews, M have score of 9.5 (173 reviews), F have 9.7 (73 reviews) and FA 9.8 (26 reviews) but I would like to know if someone had experience with two or even all three of them. Thank you for your time and patience

03-06-2015, 04:37 AM - 1 Like	#11
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	The only optical difference between the lenses is lens coatings, which improved over time and reduce flare and ghosting, and aperture blades. Here is a photo showing M 50mm aperture blades: Cosmic fly Notice how the OoF highlights are hexagonal, almost like stars? If this same photo were taken with DA 50, they would be almost perfectly round circles. But this only matters when shooting at closed aperture. Wide open (smallest f-number), all lenses produce circles. This photo was around f2.8 I think Regarding the macro extension tubes.. I think they will work for all Pentax K lenses, but the amount of extra magnification you get depends on a) focal length and b) minimum focus distance of lens. But you might lose things like AF and auto aperture. This is why many people go for the M 50mm: they plan on using it on old film cameras without automation, they plan on using it on bellows or extension tubes, they plan on adapting it to Canon or Sony camera.. For macro you don't need AF anyway, since you are working around the minimum focus distance the whole time anyway Last edited by Na Horuk; 03-06-2015 at 04:52 AM.

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03-05-2015, 03:19 PM	#2
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	At f/8 I really do not think you will be able to see any difference. I like the F 50mm f/1.7 personally but any of them or the FA 50mm f/1.4 or the DA 50mm f/1.8 will look great at f/8

03-05-2015, 03:30 PM	#3
panicAttack Forum Member Join Date: Dec 2013 Posts: 56 Original Poster	Originally posted by jatrax At f/8 I really do not think you will be able to see any difference. I like the F 50mm f/1.7 personally but any of them or the FA 50mm f/1.4 or the DA 50mm f/1.8 will look great at f/8 thanks for fast reply I dont use it only at f8, sometimes f2.8 or 5.6, (for headshot portraits) and rarely on 1.7. but mostly it is on f8 and it(was) so unbelievable sharp. But I got your point and your are right (only I don't want DA because it is crop lens and dont know about it corner sharpnes, other 1.7 are full frame lenses so when I use it on crop camera I use their best center part) cheers!

03-05-2015, 03:52 PM - 1 Like	#4
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by panicAttack are autofocus 1.7 lenses F or FA optically same as M 50 1.7 They are essentially the same optically, the main differences would be AF (duh), coatings, and build. The M 50/1.7 is a very sturdy and compact lens. Originally posted by panicAttack But I got your point and your are right (only I don't want DA because it is crop lens and dont know about it corner sharpnes, other 1.7 are full frame lenses so when I use it on crop camera I use their best center part) I own the DA 50/1.8 and have shot it on 35mm film. The short answer regarding FF compatibility is that it does vignette more wide open than my other FF fast 50s. This is obvious by direct inspection of the negative for a blank sky shot. Edge sharpness appears to be acceptable, but that is purely anecdotal. Still on my list of things to do is to conduct a head-to-head shoot-out with a few of my favorite 50s (K 55/1.8, M 50/1.7, and KMZ Helios 58/2...might also through in the XR Rikenon just for giggles). Steve Dimitrov's K-mount page uses the same optical diagram for the M, A, F, and FA versions of the 50/1.7

03-05-2015, 04:54 PM	#5
mwilky55 Site Supporter Join Date: Feb 2012 Location: Southeastern Connecticut Photos: Albums Posts: 816	Originally posted by panicAttack Greetings all, and excuse my English. Unfortunately my sharpest lens I had till today was manual 50 1.7 asashi pentax. I had some focus ring issues and wanted to repair it and completely messed things up and it cant be repaired anymore. I used it for full body studio portraits stopped at about f8 and sharpness was great from corner to center. (this is important to me) Now I want to buy another one, autofocus is great thing but only if the lens is optically the same (or even better) in term of sharpness compared to m 50 1.7. So, my question is, are autofocus 1.7 lenses F or FA optically same as M 50 1.7 or there are some differences? If they are better that's great. I have read pentax lens database reviews, M have score of 9.5 (173 reviews), F have 9.7 (73 reviews) and FA 9.8 (26 reviews) but I would like to know if someone had experience with two or even all three of them. Thank you for your time and patience While I haven't done an analysis of sharpness by aperture or anything like that, I really, really like the FA 50 1.7.

03-05-2015, 05:27 PM - 1 Like	#6
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	Hey, welcome! M, A, F, FA 50mm f1.7 lenses all follow the same optic design, with relatively small differences (mostly in coatings and shape of aperture blades), so you will not find huge differences in optical quality between them (though, some claim the F series is sharpest). Oh, and the DA 50mm f1.8 fits this as well. The main difference between these lenses is the construction and automation. The M series has no automation at all. It is beloved on these forums because it is a good, sturdy lens for a really low price, even though the prices have risen lately due to its popularity. The A series has auto-aperture, which is a very useful feature! It lets you choose the aperture on the camera body instead of only on the lens' aperture ring. F and FA series allow this as well, but they also have AF! Finally, DA series is full automatic just like the F and FA, but it doesn't even have an aperture ring (which limits its use on older film bodies). tl:dr; Get A series lens for ease of use. Get F or FA if you want AF. But honestly, the DA 50mm f1.8 is so affordable lately, it might be worth to just go for it. You get the most modern lens coatings, AF, full automation, and warranty. Sure, it is plastic, but it is still durable and much lighter. The amount of force needed to damage the plastic would probably bend or chip the older series lenses as well. I like my M 50mm f1.7, but it is not for the faint of heart. Its for hardcore users, who enjoy an old, metal, manual lens. If this fits you, then go for it If you get a good copy, any of these lenses will be great. The question is just how much automation you want, and what a good deal you can find.

03-05-2015, 07:46 PM	#7
ChristianRock Pentaxian Join Date: Jul 2013 Location: People's Republic of America Photos: Gallery \| Albums Posts: 9,910	They cost so little, you can get both the M 50 1.7 (for sentimental reasons if anything), and the DA 50 1.8 which will be just as sharp but will render out of focus areas much better than any other 50 due to the rounded blades. Personally, I am particularly fond of the Sears 50 1.7. It is as sharp as any 50 and pictures just look great.

03-05-2015, 08:31 PM	#8
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by ChristianRock They cost so little, you can get both the M 50 1.7 (for sentimental reasons if anything), and the DA 50 1.8 which will be just as sharp but will render out of focus areas much better than any other 50 due to the rounded blades. The official comparison on this site found the cheap DA 50 f1.8 did very, very well matched up against the pricey FA f.14 and DFA f2.8 Macro. Would suit you especially if it's at f8 for your flash portraits or whatever it is you do, panicAttack! :-)

03-06-2015, 03:11 AM	#9
DSims Veteran Member Join Date: Sep 2009 Location: Southern California Photos: Gallery \| Albums Posts: 3,236	The FA43 is going to be your best lens for this application, if it's in your budget. If not, the A50/1.7 or any of these that have been mentioned should do the job. I rather like the M50/1.4 I had; its rendering may be a bit different, but it's oddly beautiful: PENTAX : Select a PENTAX interchangeable lens camera or a lens model

03-06-2015, 03:59 AM	#10
panicAttack Forum Member Join Date: Dec 2013 Posts: 56 Original Poster	wow guys, thank you all! I wanted to know if it is the same optical design and got my answer, so I will probably go for FA 50 1.7 there are few selling on ebay right now. one more thing, I have macro extension rings for my old M 50 1.7 does anyone know if they can fit on FA 50 1.7? Thanks

03-06-2015, 04:49 AM	#12
panicAttack Forum Member Join Date: Dec 2013 Posts: 56 Original Poster	yes, I don't need autofocus for macro, I used those rings as macro extension or even reverse macro for my M50 1.7 so even if it was autofocus lens, it would be impossible. FA 50 1.7 and M 50 1.7 have same filter size, so I guess it will be fine. Thanks again, my choice is FA 50 1.7 It is shame there are no MTF charts for those lenses (or I just cant find them on the internet) to see how they compare with nikon 50 1.8 D or G lenses. I do have only pentax body and it will be like that for atleast until FF comes, but I see those 2 nikon fifties are so cheap even compared with used pentax autofocus primes on ebay.

03-06-2015, 04:58 AM	#13
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	Nikkor AF Nikkor 50mm f/1.8D on Nikon D7000 versus Nikkor AF-S NIKKOR 50mm f/1.8G on Nikon D7000 versus Pentax smc DA 50mm f1.8 - Side by side lens comparison - DxOMark This one lets you compare the DA 50mm on K-5 to the Nikon lenses on D7000. Usually you cannot compare data between different cameras/brands, but the K-5 and D7000 both use the same Sony 16MP sensor, with only small difference between them. So you can see the plastic DA 50mm is at least as good, if not better. What I find really great is the DA has much smaller chromatic aberration, good distortion control, high resolution and so on. The resolution of the lenses increases if you choose a K-5IIs (no AA filter) or K-3 Btw, Pentax is also producing the FA 50mm f1.4, which you can buy as new. The f1.4 lenses have a slightly different optical design, though.

03-06-2015, 05:11 AM	#14
panicAttack Forum Member Join Date: Dec 2013 Posts: 56 Original Poster	DXOmark generally prefer Nikon stuff (my opinion), so being on par or even better on same sensor is great thing. All three of them are in the same price range here in Croatia. I compared them on on k-3/d7100 also, and there is small difference in resolution, but overall DA 50 1.8 beats them all. Now will be great to compare them all with FA 50 1.7 but I am asking too much Thank you again Na Horuk, you really know how to find things.

03-06-2015, 05:27 AM	#15
yusuf Pentaxian Join Date: Nov 2008 Location: Palo Alto, CA Photos: Gallery Posts: 2,497	Originally posted by Na Horuk ... If you get a good copy, any of these lenses will be great. The question is just how much automation you want, and what a good deal you can find. I agree. In fact, you will have hard time differentiating sharpness between all the Pentax fifties (M/A/FA f1.7 or f1.4), marginal if any. The real difference is rendering.