[mhsp]

I want to thank all of you for your contribution to my question. I am not concerned about price an the list above will allow me to research and read about all the above lenses to help me decide on quality and performance and you all have given great guidelines concerning the use of each lens. I am very familiar with Canon lens and after market lenses for the Canon EOS but since I sold all my Canon stuff and now moved to Pentax I have to familiarize my self with the Pentax lens and after market lenses for my Pentax K3II. Thank you all very much for taking the time, I appreciate your comments and advice.

[mhsp]

One final question! With my PENTAX-DA 1:3.5-5.5 16-85mm ED DC WR and the rapid advance in computer-aided lens design, coupled with manufacturing technologies such as glass-moulding for the inexpensive mass-production of aspheric elements, does this mean that the gulf in image quality between primes and zooms has narrowed considerably over the past decade to make something like 15mm F4 still enough difference in quality make any practical sense? Now I ask this question because my DA 16-85 really performs extremely well especially in mid ranges. Just asking and interested in your impute.

[normhead]

The budget set...
21 ltd, 40 XS, 50 1.8.
The 21 ltd and 40 xs will fit in your pockets, no need for a camera bag.

[Alex645]

One final question! With my PENTAX-DA 1:3.5-5.5 16-85mm ED DC WR and the rapid advance in computer-aided lens design, coupled with manufacturing technologies such as glass-moulding for the inexpensive mass-production of aspheric elements, does this mean that the gulf in image quality between primes and zooms has narrowed considerably over the past decade to make something like 15mm F4 still enough difference in quality make any practical sense? Now I ask this question because my DA 16-85 really performs extremely well especially in mid ranges. Just asking and interested in your impute.

It depends. If you never make prints larger than 8x10" or only share your work on the net or computer monitor, the IQ on zooms holds up fine to a prime. But if you plan on printing A3+ size enlargements or bigger, or often crop, there is a difference. Yes, modern zooms have greatly improved and have narrowed the IQ gap with primes in modern times.

Realistically, the main advantage of primes is the faster glass for lower light capabilities and/or better bokeh. With larger apertures comes lower ISO, faster shutter speeds, and the potential of shallower DOF. And if the sweet spot is a couple stops down from max aperture, you'll get there at perhaps f/4 on a prime, whereas the zoom is typically at f/8.

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Last edited by Alex645; 12-15-2015 at 10:20 AM.

[normhead]

Take my "Find that prime test"

Or my test at 70mm... here

Or at 50mm. check here..

Simple analysis, in every test some people preferred the older zoom designs over modern primes.

I don't see a difference that is going to translate into even large scale prints.

In colour rendition, micro contrast even sharpness, people often prefer the zoom.

The best thing to do is to cover the complete range focal length in zooms. Use primes for speed, but that being said Sigma produces and excellent 18-35 ƒ1.8 lens, that is faster than my 21, or my 35 and achieves very good results. My old FA-J 18-35 is the only lens I've tested that @ ƒ5.6 gives noticeably poor results. Even my FA 35-80 considered by many on the forum to be a dog, produced results that some people preferred to my DA 35 2.4.

Lenses like the 31 ltd. are prized because of their initial sharpness, but also because of their extremely smooth bokeh, as well as the Sigma 70 macro and DA*60-250. But that is a function of the lens design. Usually primes are better, but not always. You always have to research the lens you are buying.

Once you get into fast zooms, you really don't get any advantage going with primes. My Tamron 17-50 actually outperforms my FA 50 1.8. I only use the 50 when I'm in darkened environments. A normally lit living room doesn't apply.

SO look for lightweight fast primes. I often go out with my 21 ltd. 40 XS and DA* 60-250.
And cover as much as you can with slower zooms.
Pick the zooms that cover the focal lengths you are interested in.

I wouldn't even pay attention to someone who said "primes are sharper" unless they could provide me with the kind of blind tests I've done and I could see the results.

What you learn is if you put up images from 7 lenses and ask people what they like probably over 4 of those lenses are going to get at least a 20% approval rating, the prized expensive lens isn't going to do aw well as you think it should, and the bargain basement el chemo isn't going to be as bad as you think.

And computer lens design probably goes back further than 10 years. Then you have lenses like the 77 ltd, that stand out as portrait lenses because of their design philosophy, which is a whole separate issue, the issues with super zooms verses medium zooms vs. zooms that are 3:1 or less. You can never afford to over simplify this topic.

[Rondec]

I think the answer is that primes have faster apertures (there is only one zoom with an aperture faster than f2.8 in k mount and it struggles with auto focus), they are smaller in size, usually more flare resistant, and will be sharper at wider apertures. Most lenses will be best stopped down at stop or so. That means that if you have a DA *55, it will probably have similar sharpness at f2 that your 16-85 would have at f5.6 and 55mm. If you always shoot at f5.6 or more narrow, Norm is right that you probably won't see a difference.

I use my primes for situations where I want flare resistance, or in low light situations or situations where I want more narrow depth of field. Sharpness is an added plus for a lot of apertures, but for many photos it probably isn't a deciding factor on what lens to use.

[Alex645]

Here's a comparison test I made with a series of Nikkor zooms and primes wide open at 35mm, 40mm, and 50mm. You be the judge.

Attached Images

BokehTest.pdf (1.71 MB, 193 views)

[aleonx3]

Both Norm and Rondec have covered this prime lens vs zoom lens completely with details and explanation. My thoughts on using a prime lens most of the time including all of the above comments AND one more consideration which is lens distortion. In the design of zoom lens, there is an inherent unwanted feature, which is lens distortion. I choose a prime lens often because I prefer how a prime lens renders the image more 3D like than most zoom lenses can get.

And if I have to choose a zoom lens, I would prefer a short zoom (2x or 3x) than a long or super zoom.

[mikeSF]

Buy them all, and sell the ones you don't want to keep.
It's not rocket science.

excerpted from "Confessions of a Lens Buying Addict"

[normhead]

In the design of zoom lens, there is an inherent unwanted feature, which is lens distortion.

If you can actually see it.
I've had fisheye images come out where the distortion was completely masked by the terrain being photographed. Distortion is not a problem on modern zooms. Like the above data, a prime may be better, but can you see it in the image comparing side by side? It's a technical security blanket, that may or may not improve your image, depending on what you are photographing.

IN practice sometime you'll have an image negatively affected by distortion.
Sometimes you'll have an image positively and more natural looking because of distortion.

Most of the time, it makes no difference. Remember, the human eye distorts images, your eye is used to correcting for it. Sometimes if it's not there, the subject looks artificial, other times just really weird with wide angle aspherical lenses.

I looked at your images and I don't see what you're talking about in terms of distortion, which is why a blind test is so valuable. The big question should be " am I seeing something other people are seeing, or am I just going with my biases because I know which is which?

[house]

To add one thing in the prime vs zoom discussion. Leaving the quality difference aside for me the experience of shooting primes is so much nicer. I was instantly hooked after I got the plastic fantasic (da 35), something about having a "dumb" lens is wonderful. You just raise the camera to your eye when you are in position. Misjudged the framing? Move your body, raise the camera. Snap. So much more direct! It transformed how my camera feels, made i a solid lump. Using a zoom feels so fiddly and annoying to me now. I don't shoot sports or wildlife (unless my kids qualify though so.

[normhead]

Here's a comparison test I made with a series of Nikkor zooms and primes wide open at 35mm, 40mm, and 50mm. You be the judge.

I have that same camera...mine is a Ricoflox Model VI. how weird is that. It's the camera I first started shooting with, when my dad would let me take a couple images.

---------- Post added 12-15-15 at 01:03 PM ----------

excerpted from "Confessions of a Lens Buying Addict"

One of the reasons I haven't bought new lenses lately is I still haven't sold the stuff I promised Tess I'd sell before I bought the last one.

[Kath]

Perhaps this idea is implied in what folks are saying above about zoom image quality, but I thought it worth pointing out that prime-equivalent quality is not found in some (perhaps most, or many) zooms. The ones that hold up best in image comparisons are zooms we know to have excellent quality to begin with. All too often, people spend good money on a zoom with a wide range to accommodate their needs, only to be disappointed in the lack of sharpness they see in their images.

As always, it pays to research what lenses are proven performers and make your decisions from there. It goes without saying that this applies to primes as well. Unless, of course, you're an early adopter with extra cash who's willing to stomp down the snow for those who follow.

[Alex645]

I have that same camera...mine is a Ricoflox Model VI. how weird is that. It's the camera I first started shooting with, when my dad would let me take a couple images.

---------- Post added 12-15-15 at 01:03 PM ----------



One of the reasons I haven't bought new lenses lately is I still haven't sold the stuff I promised Tess I'd sell before I bought the last one.

And my very, very first non-instamatic camera was a Yashica Mat TLR. My Ricohflex VIIS with the Ricoh 8cm lens is no longer functioning, but makes a cool prop.

[normhead]

Perhaps this idea is implied in what folks are saying above about zoom image quality, but I thought it worth pointing out that prime-equivalent quality is not found in some (perhaps most, or many) zooms. The ones that hold up best in image comparisons are zooms we know to have excellent quality to begin with. All too often, people spend good money on a zoom with a wide range to accommodate their needs, only to be disappointed in the lack of sharpness they see in their images.

As always, it pays to research what lenses are proven performers and make your decisions from there. It goes without saying that this applies to primes as well. Unless, of course, you're an early adopter with extra cash who's willing to stomp down the snow for those who follow.

I think you haven't been looking at the posted examples.

Reading reviews is info, but, I got some really good images with the kit lens. You have to be careful that differences aren't exaggerated.

You have to go extreme to get a soft zoom, like zoom ratios over 7:1, the 18-25 kind of lenses, and even those lenses can be quite sharp. The out of focus areas can be a little rough. IN fact in the past I've suggested clean out of focus areas are what you pay for in a lot of expensive lenses. But that's true in both zooms and primes.

The reason I posted example images, in this thread was to cut through the BS, and just have people pick their favourite image based on what they liked, not the preconceived biases they bring to these kinds of tests. And down that, the prime did poorly. Sure you can say if you analyse technically the prime images was better than everything bu the Tamron 17-50, but other still preferred other images, including me old 35-80. which garnered more votes than chance, because of other qualities, colour rendition and micro contrast.

The fact that a lens might be slightly technically inferior, and honestly, you can't see a difference of 150 lw/ph, the difference between great lens and an average lens. Other qualities are mor important.

I hate to keep going on about this. But if you really believe this stuff, do what I did and prove it. Get some images, post a blind poll, and check the results.

There is absolutely no way to fudge these numbers. People picked the image they thought was the prime, based on their expect that the prime would be the image they liked best.

The poll.
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/302815-35mm-find-prime.html

21% picked th prime, 79% did not.
28% thought the 35-80mwas the best image at web size, which totally goes against you idea that cheap zooms can't compete.
28% thought the Sigma 18-250 was the best image, pixel peeping. That totally goes against your ideas about long focal length zooms.

You'd also see that the most popular image in the 70mm thread was my DA*60-250, over my Sigma 70 macro, which I never would have expected. The 70 macro is an amazing lens, well corrected, and used by Imaging resources for their resolution tests whenever possible.

You're not paying attention here.

I'm not sure how despite the evidence, people can just continue to make these kinds of genreal statements, based on reviewers opinions. DO you believe reviewers, or do you believe your eyes?

This has to be evaluated lens by lens, circumstance by circumstance. If the people in my test had just gone by the general wisdom, 79% of them wouldn't have bought the lens they like best. That is a pretty dismal piece of general advice.