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02-14-2016, 03:29 AM   #1
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Prime lens for K3

Greetings!

I have a quick but not so quick question for you guys...
Getting my K3 soon with a great lens, a DA*50-135 f/2.8. But I know I'm going to want and need a prime lens for so many other reasons, my only problem is picking one out. There is the safe option of buying the DA 50mm f/1.8 on amazon for $88 but I found the Pentax M 50mm f1.7 on ebay today. I looked at both reviews and I really don't know where to make my decision. So I need you guys' input!! I am looking for really nice bokeh like everyone else and just a nice lens for portrait. Side note: it's not a matter of price, I really just want good quality for a beginner.

02-14-2016, 03:36 AM   #2
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both!

the DA 50mm is simply a great lens to shoot; it'll make your K-3 practically a point-and-shoot camera.... the M 50 is where you'll have fun, though - using a manual lens makes you so much more a part of the process....
02-14-2016, 03:36 AM   #3
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It depends on how comfortable you are with both manual focus and manual metering - the 50mm M will require that you hit the green button for stop-down metering with every shot (unless the lighting conditions are very stable); the DA50 will not.

Do you have any lenses less than 50mm? The 50-135 is a fantastic lens from everything I've heard, but not having anything wider may become a problem after a while.
02-14-2016, 03:45 AM   #4
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No the 50-135 is my only lens at the moment. It will take some learning for using manual focus but it's nothing that would hold me back from getting it.

02-14-2016, 04:09 AM - 1 Like   #5
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Do remember: on the K3, with its APS-C sensor, a 50mm lens will have a relatively narrow field of view - equivalent to a short telephoto of approx. 75mm on full frame. Both the DA50 f/1.8 and M50 f/1.7 are great lenses (I have them both), but they can be quite limiting unless your shooting style favours short telephoto. Plus, since you'll already have 50mm covered with your 50-135, you might consider something a little wider to give you added flexibility. I'd recommend any of the following as a "normal" prime:

- DA35 f/2.4 (one of my favourites, and cheap!!)
- DA35 f/2.8 Macro
- FA31 f/1.8 (I don't own one of these, but it is widely revered as one of the best - possibly the best - Pentax primes)
- DA40 f/2.8 (just a little bit long on focal length for me - equivalent to approx. 60mm on full frame - but great optically, and good for half-to-full length portrait)
- DA40 XS f/2.8 (pretty much the economy version of the DA40)

EDIT: I realise you were looking for a portrait prime, but I really think you'll have this covered with your 50-135. Adding a wider prime will open up so many other photographic possibilities

Last edited by BigMackCam; 02-14-2016 at 04:15 AM.
02-14-2016, 04:12 AM - 2 Likes   #6
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So, if you'd like to max out Portrait + Bokeh, you can do it as much as you like with the DA*50-135. You can make more bokeh by your setup rather than the lens. Basically, the distance between your camera and the subject must be less then the hyperfocal distance and the greater the distance between your subject and the background, the more bokeh you'll get. If you use a 50mm lens even a fast one, you'll not have a lot of bokeh, but if you use a longer focal length such as your 50-135 @135mm, you'll get more bokeh than with the 50mm f1.8 because: 50/1.8 < 135/2.8 .

Below is a list of lenses to select from based of bokeh potential:

Pentax FA31 f1.8: 31/1.8 = 17
Pentax DA35 f2.8: 35/2.8 = 12.5
Pentax DA40 f2.8: 40/2.8 = 14.3
Pentax DAL50 f1.8 : 50/1.8 = 28
Pentax DA*55 f1.4 SDM: 55/1.4 = 39
Pentax HD70 f2.4 Ltd: 70/2.4 = 30
Pentax FA 77 f1.8 Ltd: 77/1.8 = 43
Sigma 85 f1.4 HSM: 85/1.4 = 61
Pentax DFA100 f2.8 Macro: 100/2.8 = 36
Pentax DA*50-135 SDM @ 135mm: 135/2.8 = 48
Pentax DA*200 f2.8 SDM: 200/2.8 = 71
Pentax DA*300 f4 SMD: 300/4 = 75

The higher the number, the more bokeh potential, but be aware of the angle of view that's needed to frame your subject. Even if the DA*300 is capable of completely blurred background, its angle of view is very narrow, difficult to use especially for large subjects. The Sigma 85 f1.4 is the lens that gives you the highest bokeh capability while providing a reasonably usable angle of view, i.e more bokeh and pop than what the DA*50-135 can do @ 135mm f2.8. The DA*200 SDM would be a bokeh killer on a full frame camera, but the angle of view makes it difficult to use with the K-3 for other than head and shoulders type photos.

Best regards

Last edited by biz-engineer; 02-14-2016 at 04:31 AM.
02-14-2016, 04:55 AM   #7
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Biz-engineer, great info! that list and everything is going in my saved notes for sure.
02-14-2016, 06:27 AM   #8
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QuoteOriginally posted by aamendoza93 Quote
Greetings!

I have a quick but not so quick question for you guys...
Getting my K3 soon with a great lens, a DA*50-135 f/2.8. But I know I'm going to want and need a prime lens for so many other reasons, my only problem is picking one out. There is the safe option of buying the DA 50mm f/1.8 on amazon for $88 but I found the Pentax M 50mm f1.7 on ebay today. I looked at both reviews and I really don't know where to make my decision. So I need you guys' input!! I am looking for really nice bokeh like everyone else and just a nice lens for portrait. Side note: it's not a matter of price, I really just want good quality for a beginner.
Have you ever thought of the 55 mm f/1.8 Super / SMC Takumar? It will make a great portrait lens on a cropped sensor like the K3's. The bokeh it generates is beautiful. I prefer it to my M 50mm f/1.7.

02-14-2016, 07:12 AM   #9
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QuoteOriginally posted by aamendoza93 Quote
There is the safe option of buying the DA 50mm f/1.8 on amazon for $88 but I found the Pentax M 50mm f1.7 on ebay today. I looked at both reviews and I really don't know where to make my decision.
I have M 50mm f1.7 and its a great lens. But I got it back way before the DA 50mm f1.8 came out. Today, the DA 50mm f1.8 is sooo affordable, I would recommend it over the M 50mm. Basically the same optics, but DA has better lens coatings, rounded aperture blades (M 50mm makes a star and hexagon swirl between f2 and f3.2; DA 50 keeps it round all the way), auto-aperture, and autofocus.
The M 50mm has advantage that it has aperture ring and distance scales - this means it can be easily used on older manual focus SLR cameras, on extension tubes, and so on. But on a modern DSLR, I would recommend you buy A 50mm f1.7 or newer - basically a lens with A on aperture ring, as that makes it much easier to use! So I vote for DA 50mm f1.8. OR DA 40mm XS, OR DA 35mm f2.4 OR FA 50mm f1.4. These are the most affordable, yet still amazingly high quality primes to start with. If you buy manual glass, I suggest you get the kind that is absent in the DA lineup, like 24mm, 28mm, 85mm, 135mm..

Now, bokeh.. Biz up above wrote some numbers and stuff, but I think those could be easily misunderstood. Basically, to get apparent "big bokeh" you need a) minimum focus distance, b) lowest f-number, c) telephoto lens (higher # of mm, longest zoom on zoom lenses). 50mm is fine on APSC. Even 35mm can do it well, if you are close enough to the subject. DA 50mm f1.8 will give you more apparent bokeh at f1.8 than DA* 50-135mm would at 50m f2.8. But if you put DA 50mm to f2.8 then it would be virtually the same (sure, a little different shape, smoothness, contrast, and so on; different characteristics, but the same DoF and "size" of blur). Yes, there is a significant difference between 2.8 and f1.8. Moreso with f1.4. DA 40mm XS - a lens that is not really known for its bokeh, it is only f2.8, but for some reason, I like its bokeh. Rounded aperture blades, super compact lens (think it was smallest DSLR lens ever made when it came out, probably still is) and sharp!


tl;dr: Buy M 50mm f1.7 if you love mechanical lenses and don't mind doing extra work for the shot (also, don't pay over $60 for it) - keep in mind this lens is what, 30 years old? Buy DA 50mm f1.8 because it is affordable, fully automatic, comes with warranty, and has modern coatings. Buy A 50mm f1.4 as compromise to get some automation and some more bokeh smoothness than with f1.8 and f2.8 lenses. FA 50mm f1.4 is another great option, but costs more. It is best of both worlds, as it gives full automation and fast aperture. But where I live, it is absurdly expensive and rare.. I recommend DA 50mm, all things considered.

Last edited by Na Horuk; 02-14-2016 at 07:24 AM.
02-14-2016, 08:28 AM   #10
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The numbers that biz put above are very misleading. The DA35 f2.4 can produce 'more' bokeh than the FA31 f1.8 (simply because the min focus distance is shorter). So with the caveat 'at the same focus distance', then the numbers are semi-true. The number don't really account for the buttery quality of bokeh either. The DA40 and DA50-135 have better looking bokeh than the DA50 for example.

The DA50 f1.8 is a good lens, but it doesn't really shine until f2.5 - it's better than the old f1.7 lenses though (my opinion, others will differ). It's cheap enough that you really can't go wrong though...
02-14-2016, 09:17 AM   #11
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Even though I don't own the 50-135 the overwhelming opinion that I have heard is that it is a superb lens. So much so that people have mentioned it being prime quality in its focal lengths.

So unless you need a prime at <50 or >135, I'd say you are more than OK with your DA* 50-135

Just my opinion.

Last edited by Moropo; 02-14-2016 at 07:31 PM.
02-14-2016, 06:46 PM   #12
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QuoteOriginally posted by BigMackCam Quote
Do remember: on the K3, with its APS-C sensor, a 50mm lens will have a relatively narrow field of view - equivalent to a short telephoto of approx. 75mm on full frame. Both the DA50 f/1.8 and M50 f/1.7 are great lenses (I have them both), but they can be quite limiting unless your shooting style favours short telephoto. Plus, since you'll already have 50mm covered with your 50-135, you might consider something a little wider to give you added flexibility. I'd recommend any of the following as a "normal" prime:

- DA35 f/2.4 (one of my favourites, and cheap!!)
- DA35 f/2.8 Macro
- FA31 f/1.8 (I don't own one of these, but it is widely revered as one of the best - possibly the best - Pentax primes)
- DA40 f/2.8 (just a little bit long on focal length for me - equivalent to approx. 60mm on full frame - but great optically, and good for half-to-full length portrait)
- DA40 XS f/2.8 (pretty much the economy version of the DA40)

EDIT: I realise you were looking for a portrait prime, but I really think you'll have this covered with your 50-135. Adding a wider prime will open up so many other photographic possibilities
This is excellent advice. The only lens I would add to BigMackCam's list is the FA 43 f1.9 Ltd. It's a fine normal range lens, and has the same distinctive and special rendering as the FA 31 and FA 77 Ltd lenses - and it is significantly cheaper than they are.

The FA 43 is a fine portrait lens too. (This is at f1.9)

Last edited by Des; 02-27-2016 at 03:31 PM.
02-15-2016, 12:25 AM   #13
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QuoteOriginally posted by Des Quote
The only lens I would add to BigMackCam's list is the FA 43 f1.9 Ltd. It's a fine normal range lens, and has the same distinctive and special rendering as the FA 31 and FA 77 Ltd lenses - and it is significantly cheaper than they are.
I can't believe I didn't mention the FA43... good call
02-15-2016, 01:43 AM   #14
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QuoteOriginally posted by BigMackCam Quote
I can't believe I didn't mention the FA43
Your brain is repressing the memory because if you think about it too much you'll find the 43 irresistible.
02-15-2016, 02:02 AM   #15
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QuoteOriginally posted by Des Quote
Your brain is repressing the memory because if you think about it too much you'll find the 43 irresistible.
Nooooooooo!!! If I bought the FA43, I'd have to get the FA31 and FA77 to go with it! Must... fight... urge...
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