50-135 vs 28-105

ShiftR · 03-28-2017, 08:18 AM

I'm contemplating selling my 50-135 to get a FF zoom (for my K-1), and the *70-200 is not in the cards right now. The 28-105 has DC, is WR, and covers the meat of the range I most use the 50-135 for (which is rarely at f2.8).

With all of the hype that surrounded the 28-105 after it reached users hands, and its performance seeming to punch well above its weight, I was wondering just how good it really is compared to Pentax's older top tier lenses. Now I certainly know that the only place this lens directly exceeds the 50-135 is in focus speed, but just how close does it get to its optical quality? Could it be said it's pretty close (f4+), 7/10ths, etc?

skierd · 03-28-2017, 08:30 AM

They have completely different fields of view and the DA* is a fast constant aperture short tele zoom for APS-C while the 28-105 is a consumer grade variable aperture walk around zoom for full frame. They couldn't be more different... think of the 28-105 like a 17-70.

northcoastgreg · 03-28-2017, 08:37 AM

There may be only a little bit of overlap (in the 75 to 105 FFequiv range), but are they really all that much different in image quality? Being matched with an FF sensor, the 28-105 may have a slight resolution advantage, and being a star lens, the 50-135 may have a slight advantage in rendering and contrast, but from what I've seen from each lens, I don't think you'll see much of a difference in real world out put, particularly where they share overlapping FOVs. In any case, I'd much rather shoot the DFA 28-105 on a K-1 than the DA* 50-135. I'm not a big fan of using APS-C glass on FF cameras.

pathdoc · 03-28-2017, 08:37 AM

These two lenses have completely different philosophies of use and levels of design quality. They are chalk and cheese. In addition, it would be good to know exactly which "older top-tier lenses" you are referring to.

The DA*50-135/2.8 is designed to offer a field of view equivalent to what a 75-200 would deliver on a full-frame camera; in that sense, it is essentially the APS-C equivalent of the D-FA*70-200/2.8. In FOV terms it is a short to medium, fast tele zoom.

The D-FA 28-105 is in FOV terms a general purpose wide to short tele lens. It is not advertised as being of * (best of the best) or even Limited-level optical quality and comparison against either standard seems unwise, even if it does appear to be an unexpectedly good lens for what it is. Its utility, focal length and aperture range are, it is true, duplicated by many lenses from the late film era (F and FA series), BUT unlike any of them it is also WR (as you note) and has quick-shift focus. Practicality in the field can sometimes trump perfection in optics, and you must weigh these things up against the manner in which you intend to use the lens.

If I did not have ANY full-frame lenses AT ALL, I would unhesitatingly have bought a D-FA 28-105 to go with the K-1 I ordered yesterday. As things go, I have more film-era lenses than I can poke a stick at; and if I really need something to take my K-1 out in the wet with, I am prepared to make do with my DA18-135 in crop mode for the time being.

ShiftR · 03-28-2017, 11:19 AM

Thanks for the replies. I am/was well aware that the lenses are designed for and aimed at completely different usages. I just wanted to get an idea as to whether the difference going between the two would be painfully obvious in strict IQ terms (not the "magic dust" rendering that the Lims and *s have). From the sounds of it, I may be okay until I can step up to the 70-200.

**RGlasel** · 03-28-2017, 11:44 AM

Originally posted by ShiftR

I'm contemplating selling my 50-135 to get a FF zoom (for my K-1)

Assuming you are going to use the K-1 as your primary/only body, then I would say that this comment:

Originally posted by northcoastgreg

I'm not a big fan of using APS-C glass on FF cameras.

should decide the matter for you. If you aren't taking advantage of f2.8 with the 50-135, it's better optical resolution at f4 won't compensate for throwing away most of the K-1's pixels by using it in crop mode. Personally, better AF is more than just a handling advantage, it also results in better images, so I'd include that in the plus column for the IQ of the 28-105 as well.

skierd · 03-28-2017, 01:00 PM

From straight image quality terms, yes there will be a significant difference. Images from the 50-135 on the k1 will have heavily vingnetted and black corners or be limited to 15mp. The 28-105 will cover the whole frame, immediately giving it an advantage in the corners, and probably be close enough at f8 over the shared range with complete coverage. There is also no other Pentax designed option currently in production for the K-1 for that focal range, though the Tamron developed 24-70 is also excellent for that range on FF.

So in short, no, the 28-105 doesn't replace the 50-135 on aps-c. And the 50-135 isn't designed for the k-1, so yes the 28-105 is the better choice on FF.

But the 28-105 is not a replacement for getting the 70-200 to replace the 50-135 when moving from aps-c to the K-1, which is what I think you asked in your original post.

Despite the fact that the same lenses will work on both bodies, they are different formats. While you can go from FF to APS-C, you can't make the smaller format lenses cover the larger format anymore than you could expect a K lens to cover the sensor on a 645Z despite the fact that there are adapters to put a 645 lens on a K camera.

Originally posted by ShiftR

Thanks for the replies. I am/was well aware that the lenses are designed for and aimed at completely different usages. I just wanted to get an idea as to whether the difference going between the two would be painfully obvious in strict IQ terms (not the "magic dust" rendering that the Lims and *s have). From the sounds of it, I may be okay until I can step up to the 70-200.

**pres589** · 03-28-2017, 01:41 PM

Originally posted by pathdoc

...

If I did not have ANY full-frame lenses AT ALL, I would unhesitatingly have bought a D-FA 28-105 to go with the K-1 I ordered yesterday. As things go, I have more film-era lenses than I can poke a stick at; and if I really need something to take my K-1 out in the wet with, I am prepared to make do with my DA18-135 in crop mode for the time being.

Hrm, wondering what the DA 18-135 is like to use in 1:1 crop mode on the K-1. Not buying a K-1 but that might be a great solution to somebody'd problems.

mee · 03-28-2017, 02:12 PM

Originally posted by ShiftR

Thanks for the replies. I am/was well aware that the lenses are designed for and aimed at completely different usages. I just wanted to get an idea as to whether the difference going between the two would be painfully obvious in strict IQ terms (not the "magic dust" rendering that the Lims and *s have). From the sounds of it, I may be okay until I can step up to the 70-200.

The D-FA 28-105 is really slow on the long end and the IQ is the worst at that place of it's focal range. It is nice for a walkaround out in daylight.. or on a tripod stopped down. But it isn't a portraiture type lens due to its slow speed and (somewhat) soft performance on the long end.

Why not get a Tamron 70-200mm f/2.8? They go for around 600 USD new.

I'm testing out the 50-135mm on the K-1 with a Kenko 1.5 pz teleconverter. It seems to eliminate most of the vignetting.. but I'll probably still buy a 70-200mm one day.

pathdoc · 03-28-2017, 03:03 PM

Originally posted by pres589

Hrm, wondering what the DA 18-135 is like to use in 1:1 crop mode on the K-1. Not buying a K-1 but that might be a great solution to somebody'd problems.

From what I recall of taking a couple of try-out shots in a store in forced full-frame mode, there's a fair bit of hood vignetting top and bottom and so I don't think 1:1 would let you get away with it, but you might get something slightly outside the regular crop zone if you were willing to set the crop manually in post. I will know for certain soon enough!!

**pres589** · 03-28-2017, 03:46 PM

Originally posted by pathdoc

From what I recall of taking a couple of try-out shots in a store in forced full-frame mode, there's a fair bit of hood vignetting top and bottom and so I don't think 1:1 would let you get away with it, but you might get something slightly outside the regular crop zone if you were willing to set the crop manually in post. I will know for certain soon enough!!

Apparently my dream of using all crop-oriented lenses on the K-1 is catching on.

pathdoc · 03-28-2017, 04:50 PM

Originally posted by pres589

Apparently my dream of using all crop-oriented lenses on the K-1 is catching on.

Not really! I did it as a sort of "I know this is absolutely not going to give me a good result but I'm itching to see how it actually turns out" thing. As it happens, it turns out pretty badly; I'll almost certainly be going to full crop mode if I use this lens, and accepting that my only gains will be in terms of the somewhat more sophisticated SR and AF that I get when compared to my K-5.

The next month or so will comprise a veritable feast of trying out film-era lenses to see how they go.

**pres589** · 03-28-2017, 05:09 PM - **1 Like**

I was running around in the 3rd party zoom reviews here on the forums and there are a couple Sigma 28-200's that are discontinued that seem to be pretty good. They're not expensive either. Film era with AF so probably a mixed bag but might be worth looking into if you need other options. Would be about like the 18-135 on crop and they're not that large physically.

mee · 03-28-2017, 06:16 PM

Originally posted by pres589

Apparently my dream of using all crop-oriented lenses on the K-1 is catching on.

Is this what you are doing? I'm in the middle of shifting most of my crop-only lenses into FF counterparts. I find not using the whole viewfinder is annoying when in crop mode. I'm not sure how you do it.. it drives me nuts. I'll just use the few crop lenses I keep on the crop body.

GeneV · 03-28-2017, 06:25 PM

I have used the 18-135 on the K1 in crop mode and in 1:1. You definitely can't use the hood in 1:1, but if the light conditions let you omit the hood, it works just fine. However, the longer I used the 28-105, the less often I downshifted to the 18-135 for a compact option. The better choice for me is to carry the compact and cheap M200/4 with the 28-105 to get that range without the bulk of the 70-200.

The 50-135 is a favorite on crop sensors, and that is where it will stay. Except for the size, everything about the 70-200/2.8 (Tamron in my case) is superior on FF, and I have not been tempted to do more than test the 50-135 on the K1.

03-28-2017, 08:18 AM	#1
ShiftR Forum Member Join Date: Aug 2010 Location: Virginia Posts: 62	50-135 vs 28-105 I'm contemplating selling my 50-135 to get a FF zoom (for my K-1), and the *70-200 is not in the cards right now. The 28-105 has DC, is WR, and covers the meat of the range I most use the 50-135 for (which is rarely at f2.8). With all of the hype that surrounded the 28-105 after it reached users hands, and its performance seeming to punch well above its weight, I was wondering just how good it really is compared to Pentax's older top tier lenses. Now I certainly know that the only place this lens directly exceeds the 50-135 is in focus speed, but just how close does it get to its optical quality? Could it be said it's pretty close (f4+), 7/10ths, etc?

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03-28-2017, 08:30 AM	#2
skierd Veteran Member Join Date: Mar 2011 Location: Fairbanks, AK Photos: Gallery Posts: 1,472	They have completely different fields of view and the DA* is a fast constant aperture short tele zoom for APS-C while the 28-105 is a consumer grade variable aperture walk around zoom for full frame. They couldn't be more different... think of the 28-105 like a 17-70.

03-28-2017, 08:37 AM	#3
northcoastgreg Pentaxian Join Date: Feb 2010 Location: Northern Michigan Photos: Gallery \| Albums Posts: 6,175	There may be only a little bit of overlap (in the 75 to 105 FFequiv range), but are they really all that much different in image quality? Being matched with an FF sensor, the 28-105 may have a slight resolution advantage, and being a star lens, the 50-135 may have a slight advantage in rendering and contrast, but from what I've seen from each lens, I don't think you'll see much of a difference in real world out put, particularly where they share overlapping FOVs. In any case, I'd much rather shoot the DFA 28-105 on a K-1 than the DA* 50-135. I'm not a big fan of using APS-C glass on FF cameras.

03-28-2017, 08:37 AM	#4
pathdoc Pentaxian Join Date: Mar 2015 Photos: Gallery \| Albums Posts: 6,381	These two lenses have completely different philosophies of use and levels of design quality. They are chalk and cheese. In addition, it would be good to know exactly which "older top-tier lenses" you are referring to. The DA50-135/2.8 is designed to offer a field of view equivalent to what a 75-200 would deliver on a full-frame camera; in that sense, it is essentially the APS-C equivalent of the D-FA70-200/2.8. In FOV terms it is a short to medium, fast tele zoom. The D-FA 28-105 is in FOV terms a general purpose wide to short tele lens. It is not advertised as being of * (best of the best) or even Limited-level optical quality and comparison against either standard seems unwise, even if it does appear to be an unexpectedly good lens for what it is. Its utility, focal length and aperture range are, it is true, duplicated by many lenses from the late film era (F and FA series), BUT unlike any of them it is also WR (as you note) and has quick-shift focus. Practicality in the field can sometimes trump perfection in optics, and you must weigh these things up against the manner in which you intend to use the lens. If I did not have ANY full-frame lenses AT ALL, I would unhesitatingly have bought a D-FA 28-105 to go with the K-1 I ordered yesterday. As things go, I have more film-era lenses than I can poke a stick at; and if I really need something to take my K-1 out in the wet with, I am prepared to make do with my DA18-135 in crop mode for the time being.

03-28-2017, 11:19 AM	#5
ShiftR Forum Member Join Date: Aug 2010 Location: Virginia Posts: 62 Original Poster	Thanks for the replies. I am/was well aware that the lenses are designed for and aimed at completely different usages. I just wanted to get an idea as to whether the difference going between the two would be painfully obvious in strict IQ terms (not the "magic dust" rendering that the Lims and *s have). From the sounds of it, I may be okay until I can step up to the 70-200.

03-28-2017, 11:44 AM	#6
RGlasel Site Supporter Join Date: Sep 2013 Location: Saskatoon Photos: Gallery \| Albums Posts: 3,229	Originally posted by ShiftR I'm contemplating selling my 50-135 to get a FF zoom (for my K-1) Assuming you are going to use the K-1 as your primary/only body, then I would say that this comment: Originally posted by northcoastgreg I'm not a big fan of using APS-C glass on FF cameras. should decide the matter for you. If you aren't taking advantage of f2.8 with the 50-135, it's better optical resolution at f4 won't compensate for throwing away most of the K-1's pixels by using it in crop mode. Personally, better AF is more than just a handling advantage, it also results in better images, so I'd include that in the plus column for the IQ of the 28-105 as well.

03-28-2017, 01:00 PM	#7
skierd Veteran Member Join Date: Mar 2011 Location: Fairbanks, AK Photos: Gallery Posts: 1,472	From straight image quality terms, yes there will be a significant difference. Images from the 50-135 on the k1 will have heavily vingnetted and black corners or be limited to 15mp. The 28-105 will cover the whole frame, immediately giving it an advantage in the corners, and probably be close enough at f8 over the shared range with complete coverage. There is also no other Pentax designed option currently in production for the K-1 for that focal range, though the Tamron developed 24-70 is also excellent for that range on FF. So in short, no, the 28-105 doesn't replace the 50-135 on aps-c. And the 50-135 isn't designed for the k-1, so yes the 28-105 is the better choice on FF. But the 28-105 is not a replacement for getting the 70-200 to replace the 50-135 when moving from aps-c to the K-1, which is what I think you asked in your original post. Despite the fact that the same lenses will work on both bodies, they are different formats. While you can go from FF to APS-C, you can't make the smaller format lenses cover the larger format anymore than you could expect a K lens to cover the sensor on a 645Z despite the fact that there are adapters to put a 645 lens on a K camera. Originally posted by ShiftR Thanks for the replies. I am/was well aware that the lenses are designed for and aimed at completely different usages. I just wanted to get an idea as to whether the difference going between the two would be painfully obvious in strict IQ terms (not the "magic dust" rendering that the Lims and *s have). From the sounds of it, I may be okay until I can step up to the 70-200.

03-28-2017, 01:41 PM	#8
pres589 Site Supporter Join Date: Jan 2014 Location: Wichita, KS Photos: Albums Posts: 4,533	Originally posted by pathdoc ... If I did not have ANY full-frame lenses AT ALL, I would unhesitatingly have bought a D-FA 28-105 to go with the K-1 I ordered yesterday. As things go, I have more film-era lenses than I can poke a stick at; and if I really need something to take my K-1 out in the wet with, I am prepared to make do with my DA18-135 in crop mode for the time being. Hrm, wondering what the DA 18-135 is like to use in 1:1 crop mode on the K-1. Not buying a K-1 but that might be a great solution to somebody'd problems.

03-28-2017, 02:12 PM	#9
mee Veteran Member Join Date: May 2010 Posts: 7,403	Originally posted by ShiftR Thanks for the replies. I am/was well aware that the lenses are designed for and aimed at completely different usages. I just wanted to get an idea as to whether the difference going between the two would be painfully obvious in strict IQ terms (not the "magic dust" rendering that the Lims and *s have). From the sounds of it, I may be okay until I can step up to the 70-200. The D-FA 28-105 is really slow on the long end and the IQ is the worst at that place of it's focal range. It is nice for a walkaround out in daylight.. or on a tripod stopped down. But it isn't a portraiture type lens due to its slow speed and (somewhat) soft performance on the long end. Why not get a Tamron 70-200mm f/2.8? They go for around 600 USD new. I'm testing out the 50-135mm on the K-1 with a Kenko 1.5 pz teleconverter. It seems to eliminate most of the vignetting.. but I'll probably still buy a 70-200mm one day.

03-28-2017, 03:03 PM	#10
pathdoc Pentaxian Join Date: Mar 2015 Photos: Gallery \| Albums Posts: 6,381	Originally posted by pres589 Hrm, wondering what the DA 18-135 is like to use in 1:1 crop mode on the K-1. Not buying a K-1 but that might be a great solution to somebody'd problems. From what I recall of taking a couple of try-out shots in a store in forced full-frame mode, there's a fair bit of hood vignetting top and bottom and so I don't think 1:1 would let you get away with it, but you might get something slightly outside the regular crop zone if you were willing to set the crop manually in post. I will know for certain soon enough!!

03-28-2017, 03:46 PM	#11
pres589 Site Supporter Join Date: Jan 2014 Location: Wichita, KS Photos: Albums Posts: 4,533	Originally posted by pathdoc From what I recall of taking a couple of try-out shots in a store in forced full-frame mode, there's a fair bit of hood vignetting top and bottom and so I don't think 1:1 would let you get away with it, but you might get something slightly outside the regular crop zone if you were willing to set the crop manually in post. I will know for certain soon enough!! Apparently my dream of using all crop-oriented lenses on the K-1 is catching on.

03-28-2017, 04:50 PM	#12
pathdoc Pentaxian Join Date: Mar 2015 Photos: Gallery \| Albums Posts: 6,381	Originally posted by pres589 Apparently my dream of using all crop-oriented lenses on the K-1 is catching on. Not really! I did it as a sort of "I know this is absolutely not going to give me a good result but I'm itching to see how it actually turns out" thing. As it happens, it turns out pretty badly; I'll almost certainly be going to full crop mode if I use this lens, and accepting that my only gains will be in terms of the somewhat more sophisticated SR and AF that I get when compared to my K-5. The next month or so will comprise a veritable feast of trying out film-era lenses to see how they go.

03-28-2017, 05:09 PM - 1 Like	#13
pres589 Site Supporter Join Date: Jan 2014 Location: Wichita, KS Photos: Albums Posts: 4,533	I was running around in the 3rd party zoom reviews here on the forums and there are a couple Sigma 28-200's that are discontinued that seem to be pretty good. They're not expensive either. Film era with AF so probably a mixed bag but might be worth looking into if you need other options. Would be about like the 18-135 on crop and they're not that large physically.

03-28-2017, 06:16 PM	#14
mee Veteran Member Join Date: May 2010 Posts: 7,403	Originally posted by pres589 Apparently my dream of using all crop-oriented lenses on the K-1 is catching on. Is this what you are doing? I'm in the middle of shifting most of my crop-only lenses into FF counterparts. I find not using the whole viewfinder is annoying when in crop mode. I'm not sure how you do it.. it drives me nuts. I'll just use the few crop lenses I keep on the crop body.

03-28-2017, 06:25 PM	#15
GeneV Veteran Member Join Date: Oct 2008 Location: Albuquerque NM Photos: Albums Posts: 9,830	I have used the 18-135 on the K1 in crop mode and in 1:1. You definitely can't use the hood in 1:1, but if the light conditions let you omit the hood, it works just fine. However, the longer I used the 28-105, the less often I downshifted to the 18-135 for a compact option. The better choice for me is to carry the compact and cheap M200/4 with the 28-105 to get that range without the bulk of the 70-200. The 50-135 is a favorite on crop sensors, and that is where it will stay. Except for the size, everything about the 70-200/2.8 (Tamron in my case) is superior on FF, and I have not been tempted to do more than test the 50-135 on the K1.