Prime Lenses

Discussion in 'Pentax' started by revolver, Sep 6, 2015.

  1. I am about to take the next step and move into dedicated focal lengths. I was planning on starting with a Pentax smc 50 f1.8 thats been being advertised for under a 100 bucks lately at B&H
    but while looking at it, its the equivalent of a 76 MM because of the whole conversion thing between SLR and DSLR.

    would the 35 mm that would actually be 52 MM be closer to the "nifty fifty" ideal that seems to be the "perfect lens" as some would say?


    whats the difference between these two 50MM lenses

    I think this might make a great addition too. for 60 bucks why not?
  2. stemked

    stemked Moderator

    With a cropped sensor you are right the crop is like 76mm, but the perspective is not (I hope I have this right).
    The two lenses you listed re the same (you have the same link listed).
    I like the 50mm f1.8 which I got for free with a lens purchase. Since I got it I no longer use my 50mm f1.7 A, which was a very nice lens. Over the years I've owned many including the M42 50 f1.4 SMC Takumar, 50mm f1.4 A, 50mm f1.4 M, 50mm f2.8 F macro, 50mm f2 A,and 40mm f1.8 M pancake. All fine lenses that I realize I'll likely be whittling down, save the macro and 50mm f1.4 A. While in Japan I played with the 55mm f1.4 DA, that was one sweat lens. Too much for my blood (and at this point I already look like I've got too big a fetish for the focal length).
    The main issues with the Takumar you listed are 1) You will have to shoot and expose manually and 2) I'm pretty sure the lens had limited coatings (not the classic SMC) Therefore glare maybe a bit of an issue, but why not try? One of my all time favorite cheap-o lens is a Spirltone 135mm f2.8 m42 lens, no coatings and very soft, I love the effect, great for portraits.
  3. The discussion 50 vs 35mm has been long, even in fullframe land.
    A single focal length ideal for one might not be ideal for others. To find out what works for you ask some statistics software, fed with all your zoom shots, not me.
    I do believe 50mm make a lot of sense as a single prime in an APS C shooter's bag. A fast short portrait lens! - Even stabilized on Pentax.
    Get it. - It should be worth the $$s. Add a 24mm if you need it. - The Sigma f1.8 is bulky. - A Fuji compact instead? Or some slow k-mount 24mm? - The 12-24mm f4 does well enough for my taste, so I haven't looked at the current crop of wide primes.
    I have a 6x6 SLR with only a 120mm f2.8 lens for it. And if I go out with just primes its 24 50 135mm and 2 bodies.
    As much as I sound like a 35 & 85mm instead of 50mm (for FF) hardliner right now, I confess: there are moments when 50mm FOV is nice to have. I just couldn't be bothered to either shoot my 35mm f2 M lens or buy a new AF version for Pentax yet.
    If dropping back to zooms is an option I'd recommend a short portrait lens as the most important fast prime. - Shooting family with something wider wide open makes little sense since you 'd probably appreciate everybody in focus.
    I'm not sure about the niffy fiffy discussion / idiom. I guess its about the inexpensive 50mms on APS that earn professional portrait shooters' bread & praise for it?
  4. You might want to try some Takumar manual lenses that to me are easier to control than the DA AF lenses...
  5. AJG


    Two comments: perspective is determined by distance, not lens focal length. The 50 appears to be a "longer" focal length on APS-C cameras because the chip is smaller than 35 mm film and you have to be farther away to take in the same amount of subject than you would with a film camera, so the comparison with a 76 mm lens on film is valid.
    Second, I used to own two of the linked 135 mm lenses for theater work when I did that on both B&W and slide film. They were both good on film, but I found them to be especially flare prone on digital, as was the 35-105 f/3.5 A series zoom. You might like the effect, but don't backlight anything unless you like lens flare.
  6. sorry about the same link to the 50's

    this is the second one listed as "normal" for some reason
  7. Douglas, I figured the Takumar was manual. I was fooling around with my original Pentax 50 mm 1.2 manual lens over the weekend and liked it. I used that lens primarily with my K1000 for 30 years so the manual aspect doesnt bother me with the 135mm. besides, sometimes that Af with its multi segment 11 or 18 point focusing sometimes F***'s up my shots and has a mind of its own.

    So being that we have determined that the 50 is actually 76mm would it be pratlical to go with the 35 mm which would give me the 50mm I am loking for and not have to "step further back"?

    Harry, for 59 bucks its almost like a why not.

    I tried posting my Asunuma screw mount with 2XTC in the classified with no hits. maybe I should see if they have a bayonet to screw mount adapter and checkout that lens on the K50

    thanks for all your replies....always very helpful

    oh and Jochen, nifty fifty is a Canon reference I believe and there was this article on also
  8. AJG


    I have used a 35 f/2 A series on my Pentax DSLRs and like it quite a bit for those times when I need f/2. It's worth looking for A series versus M or earlier K mount for manual focus because the metering works a lot better than the "instant stop down" method used for the older lenses. If you want to spend more, the new 35 mm f/2.8 Macro is a great lens--compact, well built, very sharp, and focusing down to 1:1. There is newer weather resistant version, so the first version might be available used for a decent price.
  9. As previous posters have pointed out, on the crop sensor of the dSLR, while a 50mm lens is still a 50mm lens, the field of view is altered by approx. 1.54x on current Pentax digital cameras. Thus, a 50mm prime now makes a nice portrait focal length similar to what the 77mm was on SLR film, while a 35mm lens will get you closer to the traditional "normal" focal length of a 50mm-55mm on film.

    That being said, "normal" would exist in a range on dSLR from about 24mm-40mm. Each photographer has their own preference for "normal", and you will see 24, 28, 35, and 40 bantered around regularly. The DA Limited 21mm will be most similar to the 35mm used on film for that "wide'ish" photojournalism look.
  10. the "nifty fifty" ideal that seems to be the "perfect lens" as some would say​
    I'm not a Pentax shooter, so I cannot comment on the virtues of individual lenses (apart from having an itch for an old manual Pentax body to try some). But, in general, working with fixed focal length lenses doesn't necessarily take things to a new level. It's a choice - sacrifice flexibility of a zoom, gain larger apertures, smaller and lighter lens. And it's a matter of preference too - some people just want that flexibility to zoom, some don't. I prefer shooting primes; it helps me understanding up front how things will end up somehow. I've got a reasonable selection of focal lengths. None of them is perfect all the time. None of them is ideal as they're all flawed in some way. So, no need to follow directions on what would be the perfect lens - it doesn't exist.
    There is no need to do all the "equivalent focal length" mathematics, really. Apart from the correct statements already made that focal length doesn't change, it's about what you end up seeing in your viewfinder. It doesn't really matter how you call that, it's what the image is going to look like that matters.
    I assume you currently have a zoomlens for your DSLR. Do the simple thing: set it to a specific focal length (35, or 50, or 24) for a day or two, and go out and use it. Do you like the view of that focal length, is it useful to your style, or not? Or, as Jochen said, check EXIF data of the photos you already made - which focal lengths do you use a lot? Narrow down this way which focal length works for you, and then start searching. I could tell you which focal lengths I prefer, but my style of photography and approach is probably different, so it's ultimately rather meaningless. If you like shooting prime lenses, part of it is finding the focal length that resonates most with you. And if others think it is an odd choice - so be it. It has to work for you.
  11. If you're thinking of using this prime as a single walk-around lens to shoot with a simple & minimal kit, the 35 might be a little more comfortable and flexible than the 50. On the other hand, the 50 might be a better choice if you're looking to make tighter compositions with more subject-background isolation (throwing the background out of focus, etc.). The 50's main attraction is that it has generally the cheapest way to get a fast lens. Either one offers good optical quality so it comes down to how you're thinking of using it. This said, I think the DA50/1.8 and DA35/2.4 are both perfectly fine ways to introduce yourself to prime lenses.
    Those 'two' 50mm lenses have the same URL so I don't know what two lenses you might be referring to.
    The 135/2.5 Takumar is probably nothing 'special' and in addition to being manual focus, as a pre-'A' lens, will be a little less convenient to use, requiring stop-down metering. I should note that the price is reasonable but also not 'special', as it's similar at KEH and can be found for less elsewhere. As you note though, that's not a lot of money so it's easy to imagine extracting $60 worth of enjoyment out of it...and like the 50, that's as fast as you're going to get without a much more significant price tag. Some user reviews of this lens here.
  12. If you already have a 50/2 lens, you can use that on your DSLR just fine. Only buy the new DA one if you need/want auto focus. With that covered, I would look at the DA 35 if I were you. I like that focal length a lot. Looks similar to a 50 when used on a film body, that's "normal" to me!
  13. Having walked around with the DA* 55 in the city a lot recently... it depends on what you shoot.
    If you want to take pictures of scenes that are in front of you, like store fronts, scenes that size, you'll have to be always well across the street... and get parked cars in the view. A "wide" angle focal length like 16, 24 on a crop sensor, yeah, you emphasize the foreground in shots and have to be careful with composition. But in stepping back to take in a bigger scene with a 50, you increase the foreground over what you'd have with say 18mm (or something else that is way past the 1.5 conversion factor.) If you want to do scene-type snapshots with a 50mm on a crop sensor in a city, yes, it can be well done! But you'll find it frustrating because you really have to pick and compose your shots. I like prime lenses. But shooting in a big city just presents you with so many "forced" perspectives where you have to give up the whole composition (i.e. "perspective") if you can't change focal length. Or else be stuck with heavy cropping or heavy image stitching... no fun.

    Shooting with one prime only will make you a better photographer if you work at it because sometimes you really have to work a completely different angle on a subject to get a good photo than if you had a choice of focal ranges.
    My personal ideal setup includes the 12-24, a 24-70 2.8, and a cheap 70-200. It's just not realistic to handhold a telephoto zoom at night... a 2.8 lens is barely doable at low ISO as it is. So I go for the slow long zoom with the 'ol tripod if I have to.
    Or my ideal setup is the DA14/2.8, FA*24/2, DA*55/1.4, and D-FA 100mm Macro 2.8 WR. Because I love night street shooting and all four are quite usable at f/2.8. It even leaves you room to think you need an FA 77 Ltd and you can add the FA 35/2 if you really like that 50mm perspective.
    And yes. A 50mm on APS-C is close to a 75mm equivalent perspective on full-frame, when you are shooting the same composition in the viewfinder on each. You will step back further with the 50mm on 1.5 because of the narrower field of view, and you'll be at the 75mm full-frame distance when the same composition that's in the 75mm viewfinder is in your 50mm viewfinder. It works.

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