M50/1.7 vs M50/2

pschlute · 03-12-2017, 05:52 PM

Originally posted by butangmucat

Just curious, how much worse is the M50/2 compared to M50/1.7?.

Yep I had to laugh too. The M 50 1.7 is a classic stellar performer of a lens. Very sharp from f2.0.

The 50mm f2.0 has one less element and is not as good a performer according to tests done many moons ago. In the real world I doubt you could tell the difference though.

I suggest you use the f2 lens and see what you think, and in the meantime have a go at cleaning the 1.7 lens yourself. They are so cheap it is not worth getting it professionally done.

pschlute · 03-12-2017, 05:59 PM

Originally posted by butangmucat

Wait, there's a Taiwan version?

My copy came with a ME Super, and reads "Asahi Opt. Co., Japan smc PENTAX-M 1:2 50mm" and has an S/N in the 555xxxx range. Is this the earlier version or the later Taiwan version?

Note the difference in the two images. Yours was made in Japan.

**niceshot** · 03-12-2017, 06:21 PM

Originally posted by butangmucat

Hello,

Just curious, how much worse is the M50/2 compared to M50/1.7? I received both for free by chance, but the 1.7 seems to have some trouble with fungus. It seems that many reviewers on the forum don't like M50/2.

Sincerely

Read your other thread, in your case not to much of a difference.

---------- Post added 03-12-17 at 09:25 PM ----------

Originally posted by pschlute

Yep I had to laugh too. The M 50 1.7 is a classic stellar performer of a lens. Very sharp from f2.0.

The 50mm f2.0 has one less element and is not as good a performer according to tests done many moons ago. In the real world I doubt you could tell the difference though.

I suggest you use the f2 lens and see what you think, and in the meantime have a go at cleaning the 1.7 lens yourself. They are so cheap it is not worth getting it professionally done.

HE cant even use a manual Lens and you are telling him to clean a Lens, LOL, THAT MAKES ME LAUGH

ScooterMaxi Jim · 03-12-2017, 06:28 PM

Who knows what the deal is with the serial numbers. Note that the Japan designated version is a higher serial number.

For the non-Japan sourcing, my recollection is that the nation of origin was indicated as an inset on the aperture ring. Really, honestly, this wasn't high in my priorities in my youth... and at this stage in life roughly 40 years later my recollections might not be Gospel. I will say, though, that Pentax did not screw around with the origin or tolerances on f/1.7 lenses which were highly respected in the day - for good reason. As for the f/2 lenses, they got slapped on a lot of K1000s and shipped off to the high school photo classes. QC not a priority. Some of the f/2 were just fine, but not all of them. We saw a lot of those come through my photo shop.

butangmucat · 03-12-2017, 06:31 PM

Originally posted by niceshot

Read your other thread, in your case not to much of a difference.

---------- Post added 03-12-17 at 09:25 PM ----------

HE cant even use a manual Lens and you are telling him to clean a Lens, LOL, THAT MAKES ME LAUGH

Well I do know how to focus an MF lens, but I don't think that the Tamron SP 90mm Macro can focus on a 1mm dot inside a lens and show it clearly.
That Tamron is my only macro besides the Industar-61 L/Z.

**niceshot** · 03-12-2017, 06:34 PM

Originally posted by butangmucat

Well I do know how to focus an MF lens, but I don't think that the Tamron SP 90mm Macro can focus on a 1mm dot inside a lens and show it clearly.

If it is that small it wont impact your image quality

butangmucat · 03-12-2017, 06:36 PM

Originally posted by niceshot

If it is that small it wont impact your image quality

I am more worried about fungus growth and spreading to my other lenses. I am taking some my gear to the humid southern China in a few months. So if it is fungus I will either disinfect it or dispose it.

**niceshot** · 03-12-2017, 06:38 PM

Originally posted by butangmucat

I am more worried about fungus growth and spreading to my other lenses. I am taking some my gear to the humid southern China in a few months. So if it is fungus I will either disinfect it or dispose it.

that is a myth, just use it. I suspect it is a metal flake or condensed grease. You can get another lens to help you look inside of that Lens, then you will know.

butangmucat · 03-12-2017, 06:39 PM

Originally posted by niceshot

Read your other thread, in your case not to much of a difference.

---------- Post added 03-12-17 at 09:25 PM ----------

HE cant even use a manual Lens and you are telling him to clean a Lens, LOL, THAT MAKES ME LAUGH

I mean, if the M50/2 stands up well against M50/1.7 and is indeed a hidden gem, I might just dispose the M50/1.7 and enjoy my M50/2 as a compact MF lens for my Sony mirrorless (and send the FA43 and FA35 back to my K-S2), or if the M50/1.7 is indeed special or much better than the M50/2, I will try to clean the dot out just in case it spreads to my other lenses.

**niceshot** · 03-12-2017, 06:45 PM

Originally posted by butangmucat

I mean, if the M50/2 stands up well against M50/1.7 and is indeed a hidden gem, I might just dispose the M50/1.7 and enjoy my M50/2 as a compact MF lens for my Sony mirrorless (and send the FA43 and FA35 back to my K-S2), or if the M50/1.7 is indeed special or much better than the M50/2, I will try to clean the dot out just in case it spreads to my other lenses.

Ok first inspect it like I said with another lens or a Loupe. If it is fungus you will know. I saw a guy who took a wet sock filled it up with copper pennies and dried it a dry, after he put the lens together with the sock of pennies in a plastic bag for a few day. swears it kills the fungus. I SUGGEST THIS FOR YOU

**arnold** · 03-12-2017, 06:53 PM

Originally posted by butangmucat

I mean, if the M50/2 stands up well against M50/1.7 and is indeed a hidden gem, I might just dispose the M50/1.7 and enjoy my M50/2 as a compact MF lens for my Sony mirrorless (and send the FA43 and FA35 back to my K-S2), or if the M50/1.7 is indeed special or much better than the M50/2, I will try to clean the dot out just in case it spreads to my other lenses.

There is nothing wrong with the M50/2.0. I have several, and the one I have used is made in Taiwan. I did a review on it here on this Forum, and can assure you it will not detract from your pictures because of quality. Other factors have a vastly bigger influence, such as camera shake, aperture choice, lighting, exposure, and lastly but most importantly, the creative eye.

butangmucat · 03-12-2017, 07:04 PM

Thanks all. It is more about my questions on the relatively low user rating on this lens. I mean I have used it a few times, as a handy adapted walkaround glass on mirrorless, and it produces pictures as good as I would expect from a 50mm, but I don't quite get some the low ratings and recommend againsts in the database.

M50/2, Lens Turbo II, f5.6, wish the starbursts could be slightly more pronounced.

**niceshot** · 03-12-2017, 07:18 PM

Originally posted by butangmucat

Thanks all. It is more about my questions on the relatively low user rating on this lens. I mean I have used it a few times, as a handy adapted walkaround glass on mirrorless, and it produces pictures as good as I would expect from a 50mm, but I don't quite get some the low ratings and recommend againsts in the database.

M50/2, Lens Turbo II, f5.6, wish the starbursts could be slightly more pronounced.

Lens rating are not gospel. Use it and enjoy. And when you get thirsty for the other lens just spend $30 on E-bay

**arnold** · 03-12-2017, 07:51 PM

Originally posted by butangmucat

Thanks all. It is more about my questions on the relatively low user rating on this lens. I mean I have used it a few times, as a handy adapted walkaround glass on mirrorless, and it produces pictures as good as I would expect from a 50mm, but I don't quite get some the low ratings and recommend againsts in the database.

M50/2, Lens Turbo II, f5.6, wish the starbursts could be slightly more pronounced.

Most 50mm lenses are very good. Even a three element triplet can be remarkably good. The famous Tessar is a triplet of sorts with the last element made of two pieces glued together to help flatten the field, and the results from Tessars are excellent. The M50/f2 has five bits of glass because f2.8 is as big as a Tessar can handle. The M50/1.7 was too much for 5 elements, so a sixth was added. The f1.4 needs 7 lenses, but one should remember that every bit of glass impedes and reflects light from where you want it to go. Glass that isn't there has 100% transmission.
About the fungus in your lens, you may not be aware that fungus spoors are everywhere in the air, and will eventually enter lens-space. This is only a problem if you give them the conditions to grow - moisture and darkness for example. Yur lens is not likely to contaminate other lenses, and if it is in low humidity, growth will shut down completely. Some fungus, when it is active, produces an acid that eats into the glass. For aesthetic reasons I hate the idea of fungus in my lenses, but leave it to those more experienced to open the lens and clean it.

ZombieArmy · 03-12-2017, 08:31 PM

1mm dot? You sure that's not just dust?

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03-12-2017, 05:52 PM	#16
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,210	Originally posted by butangmucat Just curious, how much worse is the M50/2 compared to M50/1.7?. Yep I had to laugh too. The M 50 1.7 is a classic stellar performer of a lens. Very sharp from f2.0. The 50mm f2.0 has one less element and is not as good a performer according to tests done many moons ago. In the real world I doubt you could tell the difference though. I suggest you use the f2 lens and see what you think, and in the meantime have a go at cleaning the 1.7 lens yourself. They are so cheap it is not worth getting it professionally done.

03-12-2017, 06:21 PM	#18
niceshot Site Supporter Join Date: Mar 2014 Location: NY Photos: Gallery Posts: 1,565	Originally posted by butangmucat Hello, Just curious, how much worse is the M50/2 compared to M50/1.7? I received both for free by chance, but the 1.7 seems to have some trouble with fungus. It seems that many reviewers on the forum don't like M50/2. Sincerely Read your other thread, in your case not to much of a difference. ---------- Post added 03-12-17 at 09:25 PM ---------- Originally posted by pschlute Yep I had to laugh too. The M 50 1.7 is a classic stellar performer of a lens. Very sharp from f2.0. The 50mm f2.0 has one less element and is not as good a performer according to tests done many moons ago. In the real world I doubt you could tell the difference though. I suggest you use the f2 lens and see what you think, and in the meantime have a go at cleaning the 1.7 lens yourself. They are so cheap it is not worth getting it professionally done. HE cant even use a manual Lens and you are telling him to clean a Lens, LOL, THAT MAKES ME LAUGH

03-12-2017, 06:28 PM	#19
ScooterMaxi Jim Veteran Member Join Date: Jul 2009 Location: Minnesota Posts: 1,520	Who knows what the deal is with the serial numbers. Note that the Japan designated version is a higher serial number. For the non-Japan sourcing, my recollection is that the nation of origin was indicated as an inset on the aperture ring. Really, honestly, this wasn't high in my priorities in my youth... and at this stage in life roughly 40 years later my recollections might not be Gospel. I will say, though, that Pentax did not screw around with the origin or tolerances on f/1.7 lenses which were highly respected in the day - for good reason. As for the f/2 lenses, they got slapped on a lot of K1000s and shipped off to the high school photo classes. QC not a priority. Some of the f/2 were just fine, but not all of them. We saw a lot of those come through my photo shop.

03-12-2017, 06:31 PM	#20
butangmucat Veteran Member Join Date: Jul 2016 Posts: 709 Original Poster	Originally posted by niceshot Read your other thread, in your case not to much of a difference. ---------- Post added 03-12-17 at 09:25 PM ---------- HE cant even use a manual Lens and you are telling him to clean a Lens, LOL, THAT MAKES ME LAUGH Well I do know how to focus an MF lens, but I don't think that the Tamron SP 90mm Macro can focus on a 1mm dot inside a lens and show it clearly. That Tamron is my only macro besides the Industar-61 L/Z.

03-12-2017, 06:34 PM	#21
niceshot Site Supporter Join Date: Mar 2014 Location: NY Photos: Gallery Posts: 1,565	Originally posted by butangmucat Well I do know how to focus an MF lens, but I don't think that the Tamron SP 90mm Macro can focus on a 1mm dot inside a lens and show it clearly. If it is that small it wont impact your image quality

03-12-2017, 06:36 PM	#22
butangmucat Veteran Member Join Date: Jul 2016 Posts: 709 Original Poster	Originally posted by niceshot If it is that small it wont impact your image quality I am more worried about fungus growth and spreading to my other lenses. I am taking some my gear to the humid southern China in a few months. So if it is fungus I will either disinfect it or dispose it.

03-12-2017, 06:38 PM	#23
niceshot Site Supporter Join Date: Mar 2014 Location: NY Photos: Gallery Posts: 1,565	Originally posted by butangmucat I am more worried about fungus growth and spreading to my other lenses. I am taking some my gear to the humid southern China in a few months. So if it is fungus I will either disinfect it or dispose it. that is a myth, just use it. I suspect it is a metal flake or condensed grease. You can get another lens to help you look inside of that Lens, then you will know.

03-12-2017, 06:39 PM	#24
butangmucat Veteran Member Join Date: Jul 2016 Posts: 709 Original Poster	Originally posted by niceshot Read your other thread, in your case not to much of a difference. ---------- Post added 03-12-17 at 09:25 PM ---------- HE cant even use a manual Lens and you are telling him to clean a Lens, LOL, THAT MAKES ME LAUGH I mean, if the M50/2 stands up well against M50/1.7 and is indeed a hidden gem, I might just dispose the M50/1.7 and enjoy my M50/2 as a compact MF lens for my Sony mirrorless (and send the FA43 and FA35 back to my K-S2), or if the M50/1.7 is indeed special or much better than the M50/2, I will try to clean the dot out just in case it spreads to my other lenses.

03-12-2017, 06:45 PM	#25
niceshot Site Supporter Join Date: Mar 2014 Location: NY Photos: Gallery Posts: 1,565	Originally posted by butangmucat I mean, if the M50/2 stands up well against M50/1.7 and is indeed a hidden gem, I might just dispose the M50/1.7 and enjoy my M50/2 as a compact MF lens for my Sony mirrorless (and send the FA43 and FA35 back to my K-S2), or if the M50/1.7 is indeed special or much better than the M50/2, I will try to clean the dot out just in case it spreads to my other lenses. Ok first inspect it like I said with another lens or a Loupe. If it is fungus you will know. I saw a guy who took a wet sock filled it up with copper pennies and dried it a dry, after he put the lens together with the sock of pennies in a plastic bag for a few day. swears it kills the fungus. I SUGGEST THIS FOR YOU

03-12-2017, 06:53 PM	#26
arnold Site Supporter Join Date: Aug 2012 Location: Queensland Photos: Gallery \| Albums Posts: 4,295	Originally posted by butangmucat I mean, if the M50/2 stands up well against M50/1.7 and is indeed a hidden gem, I might just dispose the M50/1.7 and enjoy my M50/2 as a compact MF lens for my Sony mirrorless (and send the FA43 and FA35 back to my K-S2), or if the M50/1.7 is indeed special or much better than the M50/2, I will try to clean the dot out just in case it spreads to my other lenses. There is nothing wrong with the M50/2.0. I have several, and the one I have used is made in Taiwan. I did a review on it here on this Forum, and can assure you it will not detract from your pictures because of quality. Other factors have a vastly bigger influence, such as camera shake, aperture choice, lighting, exposure, and lastly but most importantly, the creative eye.

03-12-2017, 07:04 PM	#27
butangmucat Veteran Member Join Date: Jul 2016 Posts: 709 Original Poster	Thanks all. It is more about my questions on the relatively low user rating on this lens. I mean I have used it a few times, as a handy adapted walkaround glass on mirrorless, and it produces pictures as good as I would expect from a 50mm, but I don't quite get some the low ratings and recommend againsts in the database. M50/2, Lens Turbo II, f5.6, wish the starbursts could be slightly more pronounced.

03-12-2017, 07:18 PM	#28
niceshot Site Supporter Join Date: Mar 2014 Location: NY Photos: Gallery Posts: 1,565	Originally posted by butangmucat Thanks all. It is more about my questions on the relatively low user rating on this lens. I mean I have used it a few times, as a handy adapted walkaround glass on mirrorless, and it produces pictures as good as I would expect from a 50mm, but I don't quite get some the low ratings and recommend againsts in the database. M50/2, Lens Turbo II, f5.6, wish the starbursts could be slightly more pronounced. Lens rating are not gospel. Use it and enjoy. And when you get thirsty for the other lens just spend $30 on E-bay

03-12-2017, 07:51 PM	#29
arnold Site Supporter Join Date: Aug 2012 Location: Queensland Photos: Gallery \| Albums Posts: 4,295	Originally posted by butangmucat Thanks all. It is more about my questions on the relatively low user rating on this lens. I mean I have used it a few times, as a handy adapted walkaround glass on mirrorless, and it produces pictures as good as I would expect from a 50mm, but I don't quite get some the low ratings and recommend againsts in the database. M50/2, Lens Turbo II, f5.6, wish the starbursts could be slightly more pronounced. Most 50mm lenses are very good. Even a three element triplet can be remarkably good. The famous Tessar is a triplet of sorts with the last element made of two pieces glued together to help flatten the field, and the results from Tessars are excellent. The M50/f2 has five bits of glass because f2.8 is as big as a Tessar can handle. The M50/1.7 was too much for 5 elements, so a sixth was added. The f1.4 needs 7 lenses, but one should remember that every bit of glass impedes and reflects light from where you want it to go. Glass that isn't there has 100% transmission. About the fungus in your lens, you may not be aware that fungus spoors are everywhere in the air, and will eventually enter lens-space. This is only a problem if you give them the conditions to grow - moisture and darkness for example. Yur lens is not likely to contaminate other lenses, and if it is in low humidity, growth will shut down completely. Some fungus, when it is active, produces an acid that eats into the glass. For aesthetic reasons I hate the idea of fungus in my lenses, but leave it to those more experienced to open the lens and clean it.

03-12-2017, 08:31 PM	#30
ZombieArmy Pentaxian Join Date: Jun 2014 Location: Florida Posts: 3,210	1mm dot? You sure that's not just dust?