The Prime Experiment


No question about it: I am a zoom guy.  In other words: I am not a change lens guy.  After all, why expose your sensor to dust needlessly by changing lenses?  Why lug around more lenses than you need?  Why limit yourself to the specific field of view on the particular lens you happen to have mounted on your camera?  Why?  Why?  Why?

Well, here are five reasons why…

I’ve heard and read that many fine professionals and accomplished artists actually prefer to shoot with single focal length prime lenses.  This, despite the fact that they can be limiting, can force you to have to carry multiple lenses when one do-it-all zoomer will cover the full range of near and far possibilities, and the reality that you can accidentally introduce dust and particles into the delicate innards of your camera body whenever you swap out lenses.  Given those downsides, why would those professionals and artists prefer prime lenses?

As an experiment, I mounted the highly respected Pentax 15 Limited lens onto my K5 and spent about a week walking around with only that lens.  Granted, it’s a pretty wide point of view (equivalent to 22.5mm on a full frame camera) and wide angle shooting isn’t everyone’s cup of tea.  In fact, some argue that if you’re going to walk around with only one lens, make it the relative “normal” (equivalent to 50mm full frame or about 35mm on a 1.5 cropped sensor) one.  This is the focal length that many post-40somethings (like me) grew up with on their all manual cameras back in the day and it’s considered normal because it approximates what we ourselves see through our own eyes.  Personally, I’ve found the 35mm to be a bit restrictive when I walk around with one lens, so I thought I’d try the 15mm on for size.


In short, I’m glad I did.  I found the lens to be sharp and adequately wide for my use.  I enjoyed the fact that unlike most ultra-wide zooms I’ve used, there wasn’t excessive flare.  In fact, the 15 Limited seems to tame the sun; often I shot directly into it without worry, knowing that the resulting starburst pattern could be interesting as opposed to the offending flare that is typically generated in such situations.

Here are five observations after one week of shooting with one fixed focal length lens.

Sharper images. Compared to my very decent zoom lenses, the shots taken with the prime lens almost always resulted in sharper images.  Naturally out-of-the-camera sharpness is always superior to manufactured-in-post-process sharpness due to the fact that software-based sharpening can introduce artifacts and other unsightly effects.  Zooms are complicated beasts and some compromises are required in their design and manufacture.  Primes are simpler with far fewer moving parts (only focus and aperture, not focal length manipulation) and, thus, consistent sharpness, edge to edge, is typical.


Improved low light capabilities. Though my Pentax is an f4 and not exactly a speed demon, I have also been playing around with some faster Pentax glass and generally speaking, you can get faster and wider aperture lenses in the prime variety than you can with zooms.  You’re not going to find any f1.4 zooms at B&H.  Because of the ability to open up the lens to a wider aperture than on comparable zooms, you can play around longer as the sun drops without boosting ISO and introducing digital noise.  As newer camera bodies improve their low light abilities, this advantage is lessening, however.


Better DOF control. Because of the wider apertures, depth of field control and the ability to isolate the subject against a blurry background is better with the prime.  On the Pentax 31 f1.8 I’ve used, you get much, much better isolation than at the approximately f4 (or smaller) you get in that range on typical zoom or even f2.8 on a better quality lens.

Better bokeh. This relates to the above, but my experiment included isolating subjects at f4 and comparing the images to my zooms.  In all cases, I found the bokeh (out of focus characteristics of the background) to be smoother and more pleasing.

Forces you to think. This is the best reason of all.  You’ve heard the expression that with primes, you need to “zoom with your feet“.  I found that that’s absolutely a true statement.  And when I was zooming back and forth, I found myself more naturally and instinctively thinking about composition and moving the camera along other planes as well.  For example, as I proceeded forward and back, looking through the viewfinder, I also moved up, down and side to side relative to the subject.  That helped expand my creativity and see the environment in new ways… ways I simply would not have had the 18-135 been mounted on my camera.


As we’ve discussed here on 2 Guys Photo, it’s vital to challenge yourself in order to improve your photography.  Next time you head out, grab one or maybe two prime lenses and leave the zooms behind.  And see what happens…

Posted by Rey

This entry was posted in Gear & accessories, Images, Learning and tagged , , , , . Bookmark the permalink.

13 Responses to The Prime Experiment

  1. jsherman999 says:

    Nice overview, Rey, and I especially like that B&W forest/shadow shot.

    Hope you have as much fun with the 15 as I’ve been having!

  2. Enjoyed your post, I often leave my zooms home and take one of my old manual focus primes with me when commuting back and forth to work. I makes me work at it more and (I think) makes photography more fun. Especially when you are taking the opportunity to manual focus with lenses that are built for it. LOVE the feeling.


  3. DGuidas says:

    All good points along with good photos. When my 17-70 was in for repair last year, I spent 2 weeks shooting with only my 50mm Super-Takumar. Talk about forced to think, whew! Although I now use zooms a lot for versatility, a DA15 is definitely on my next purchase radar.

  4. LaRee says:

    I enjoyed this entry. I also mostly use a zoom lens as I believe it gives me more flexibility. BUT I absolutely LOVE my primes too. I always have at least one with me. It is an easy thing to do with the 50 1.4, DA*15, DA*35, FA*77 and FA*43 to choose from. Actually I have a few old classic Pentax lenses that I’ve been having a hankering to get out and use. It has been far too long since I shot with them. The Pentax A200 f/4 is sleek and slick and so compact! The old Tokina 24mm 2.8 is nice and I’ve not used it for too long. So thank you for the reminder of the joy of working with these small compact and solid lenses. Any extra thought/effort is always paid off with wonderful images. You’ve some very nice examples of that here.

  5. This is really interesting to me because one of the reasons I don’t shoot with a DSLR is that I’m afraid to change lenses. If I thought I could get one lens that would work in the majority of situations, that would be a selling point:-) I really liked the light, shadows, and clarity of that indoor hallway shot.

  6. happypoppeye says:

    Great post. Personally, I’m not a zoom guy and I’m not a prime guy. I’m a one lens guy. I hate changing lenses and I hate carrying crap. I used an 18-200 exclusively for almost two years. Last trip I switched to a 35 1.8. Guess what, I didn’t feel like I missed anything, and actually realized that it’s not a zoom or prime question, just a carrying crap question for me and the control over depth and size of a small and fast prime really made up for the fixed FL.


    • 2guysphoto says:

      Well said, John. I’m increasingly moving over to your point of view. My brother, Ed, might argue with the characterization of the 18-200 as crap, but I do think that you trade off convenience for quality in an big way when you go with the superzooms…


  7. happypoppeye says:

    I gotta tell ya too. I used the Nikon 18-200 on a mega trip two years ago, and although I can look back and say I wish I had something better, the thing produced some great shots. It actually paid for itself about five times over with pics sold. It never let me down, and it never even hiccupped in some of the harshest places in teh world. I gotta give it credit. I should post a picture of it – it looks absolutely destroyed and is filled with dust and dirt, and yet, it workd perfectly. It’s seen me through Afghanistan, India (twice), Thailand (four times), Cambodia, China, Japan, Myanmar, Nepal, Turkey, Syria, Jordan, Egypt, Sudan, Cameroon, Nigeria, Benin, Togo, Ghana, Mali, Burkina Faso and Senegal. One full out war and two civil wars. From six months of Sahara heat to weeks in tropical rain forests. Could be the greatest photographic equipment buy I ever made. …I can’t fault it one bit.

    • Ed Spadoni says:

      Hi John – Ed here, the other half of 2 Guys. Like you, I’ve had some excellent results with my Nikon 18-200 and don’t find that there are unreasonable trade-offs for the convenience. Yes, I’m sure a bag full of primes or several shorter zooms could result in faster shutter speeds and some increase in sharpness, but then again, who wants to carry (or can afford) a bag full of lenses? Back when I did use multiple lenses, I often missed the shot because I was busy changing lenses. BTW, I also love the Nikon 35, f/1.8, my second most used lens.

      Thanks for discovering 2 Guys Photo, I hope you’ll visit often. Ed

      • 2guysphoto says:

        I think we can always debate the quality/convenience trade-off thing, but there’s another facet of this that has been intriguing me of late. It’s the benefits (vs. drawbacks) of artistic constraint. When you’re toting an 18-200, you compose differently than when you have one, let’s say, 35/1.8. I’m finding that when I’m shooting with one of my primes, I definitely begin to see (outside of the camera) in the exact perspective that the one lens I’m carrying has. So, I’m composing and framing as I’m looking around, not only when I’m looking through the viewfinder. For some reason, this very phenomenon used to frustrate me to no end… but, now I’m actually enjoying the limitation.


    • 2guysphoto says:

      John – forget the lens, what about you? You must have an amazing story yourself, having visited all those places. Military? If you send a picture of that 18-200, we’ll post it on the blog (along with an accompanying story, of course).



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