[Eagle_Friends]

Since we're grabbing things from websites, how about this bit from Popphoto about the DA* 200mm f2.8?

From Popphoto:

DA* 200mm

"CONCLUSIONS
In its superior vignetting- and distortion-control performance, this digital-only tele actually tests very much like the full-frame lenses we've evaluated on DSLRs with APS-sized sensors -- no surprise since its design is based on a 35mm lens. Its high speed and near flawless optics coupled with Pentax's sensor-based image stabilization technology helped us take dozens of satisfying pictures over several weeks of field testing. It promises the pro or serious amateur virtually distortion-free and perfectly sharp pictures, even in less-than-perfect light.


If there's a downside to this lens, we couldn't find it."


Any who, they also reviewed the 60-250mm and gave it a good score. The only down side they saw was at the long end.

[liukaitc]

I agree on many. I think it is different appoarch, different feeling of photo taking. Even one day zoom can match IQ of prime, people still will love and enjoy use prime.

[Emacs]

From photozone

Don't take photozone too seriously. There are plethora of parameters that aren't known how to measure. Moreover, he didn't even measure all params. The excellent example is the fact MTF-aperture relation changes through the focusing point distance.
Photozone's test show FA 43Ltd has the maximal MTF at f=4.0. But it only works for those conditions that guy used. For the focusing point in infinity MTF at f=4.0 just can't bring enough resolution but it becomes razor sharp at f=8.0
I'm sure DA* 200 vs DA* 60-250 is the same moment. The zoom can achieve some prime parameters within the certain conditions (but it still loses subjectively), but loses the competition in a whole.

[rparmar]

I trust Photozone more than any other review site but the limitations Emacs points out should be taken into account. There is a lot we cannot tell about a lens without proper graphs from the manufacturer. We should be petitioning Pentax to release proper MTF graphs for all their lenses. The designers have tons of information they simply don't give us. Unlike Leica, for example.

[newarts]

I'm just curious as to if the IQ of zoom lenses are up there now with prime lenses. With today's modern technology, have they moved up into the same IQ as primes? I'm sure they are probably on par with my older Takumar primes, but comparing modern day primes to zooms, how does everything work out?

I think it depends on display size and whether you crop or not.

Using Subjective Image Quality (roughly contrast averaged over 1/2-2 lp/mm on the display) as the appropriate measure, it has been demonstrated that a difference of 5% is just discernible by the average viewer. It is likely that for normal, un-cropped displays and modern zoom lenses that's not a difficult specification to meet.

So if you frame the scene with your camera and don't print billboards, new zooms can probably perform as well as primes. At low enlargements, image contrast, hence quality, is likely to be highly dependent on lens coatings and cleanliness rather than the lens' resolution limit.

Dave

[RioRico]

At low enlargements, image contrast, hence quality, is likely to be highly dependent on lens coatings and cleanliness rather than the lens' resolution limit.

And contrast can be tweaked in PP. And image impact is affected by presentation, how the image is shown. Thus within certain ranges, IQ of zooms and primes may be indistinguishable. So the difference is elsewhere: maximum aperture and thus thinness of DOF; what we can mystically call 'rendering' and 'character' (my fave); and mostly, the different discipline invoked by not being able to zoom optically.

And yes, size matters. My 18-250 or 70-210 or 100-300 zooms each have a certain physical presence at 100mm, protruding about 150mm / 6 inches from the camera body (without hoods). My little Enna Tele-Sandmar 100/4.5 sticks out just 33mm / 1.25 inches. The slow old Enna just doesn't LOOK like an intruding tele, being about half the size of a little F35-70. Rather better for street-shooting than one of those bigger guns. The newer zooms have better IQ than the Enna, but the Enna lets me get people shots where the big guys would be too intimidating. That's the same reason I'll use my little Sakar 500/8 mirror rather than a long 400mm or the Lil'Bigma 170-500, because it doesn't look like a grenade launcher.

To tally-up: Modern zooms have flexibility, decent quality, decent speed, higher prices usually, and are more prone to physical-optical problems. Primes are often smaller, faster, cheaper, sturdier, less obtrusive, more distinctive in character, and one gets more exercise using them. And should I mention longer enlarger lenses on bellows? VERY sharp and cheap and small, and they all do macro! Yada yada...

[GeneV]

And contrast can be tweaked in PP. And image impact is affected by presentation, how the image is shown. Thus within certain ranges, IQ of zooms and primes may be indistinguishable. So the difference is elsewhere: maximum aperture and thus thinness of DOF; what we can mystically call 'rendering' and 'character' (my fave); and mostly, the different discipline invoked by not being able to zoom optically.

And yes, size matters. My 18-250 or 70-210 or 100-300 zooms each have a certain physical presence at 100mm, protruding about 150mm / 6 inches from the camera body (without hoods). My little Enna Tele-Sandmar 100/4.5 sticks out just 33mm / 1.25 inches. The slow old Enna just doesn't LOOK like an intruding tele, being about half the size of a little F35-70. Rather better for street-shooting than one of those bigger guns. The newer zooms have better IQ than the Enna, but the Enna lets me get people shots where the big guys would be too intimidating. That's the same reason I'll use my little Sakar 500/8 mirror rather than a long 400mm or the Lil'Bigma 170-500, because it doesn't look like a grenade launcher.

One of the terrific things about the DA70 is that no one suspects it is a tele--especially with the hood removed. People who look through my finder are amazed. On the other hand, most of my zooms that get to that FL are pretty impressively sized.

[rparmar]

On that note I have managed to be clever with the DA16-45mm. At its full length it is actually 16mm, but anyone beside you thinks you are getting a tele shot of the other side of the room. this lets you take candid photos of them.

[Robboa]

This has been a great discussion. I have started back taking photos after 20yrs and getting used to the DSLR. I've just bought entry level gear to get started a k-r kit and a Sigma 70-300 DG f4-5.6.

I am taking pics of the kids in sports (netball and swimming), having some fun but havent got the results I want with the sigma, I've got some great shots but the f4 isnt wide enough for good bokeh, and the sharpness isnt always there... I was thinking of getting the Pentax 200mm f2.8, but have discovered these constant aperture zooms like the Sigma 70-200mm f2.8. From what I have read above and because many of my shots will be wide open, I'd expect the prime to give better IQ right?

If I go the prime and lock into a fixed 200mm its going to be a new world for me and take a bit of getting used to, but it is a lighter and smaller lens and has great reviews.

[8540tomg]

No question zoom lenses have improved dramatically over the past thirty years. As others have noted above today’s zooms, for all intents and purposes, are more than good enough for the type of work most of us do. An 8 x 10 print isn’t much of a stretch for most of them. Thirty years ago, when I got my first SLR, this was not the case. The advantages of the variable focal length are many with “fast” f2.8 zooms not all that uncommon any more. I have the DA* 16~50/2.8 zoom and unlike some I have had no SDM issues. It is a great zoom lens if a bit hefty and soft at 2.8.

That being said I still prefer the “feel” of my prime lenses to the zoom. I find I work differently with a prime attached. I tend move around more and look at different angles than I do with a zoom in hand. I know I could do the same with a zoom but for some reason I just don’t. Most of the primes I use on a regular basis are old manual focus glass and are f 2.8 or faster. As a result they are always brighter in the viewfinder and that extra speed is always there if I need it. Super fast fifties like the 1.2, and 1.4 can deliver a “look” just not possible with a zoom. You can, of course, pick one of these up quite cheaply these days.

I have no way to empirically prove it but I’m sure my DA 70/2.4 is sharper than the DA* 16~50/2.8. This is certainly true wide open although by f 5.6 the zoom is damn sharp. Every lens has a sweet spot and again I think my most of my primes, at their best, are still a little sharper than the zoom. Bear in mind I’m not speaking for all zooms but for the one I own and use a lot the DA* 16~50/2.8.

I think Twitch talked about the intimidation factor a large zoom can have on your subject. Although I use the zoom for portraits from time to time my DA 70 is my go to lens for portraits. If find my subjects are a lot more comfortable having this tiny lens pointed in their direction than the zoom.

Getting back to the original post “zoom or prime which has the best IQ?” No definitive answer is possible in the case of my gear. Zooms certainly dominate the marketplace these days but I carry both in my bag at all times. They are just tools to get the job done. There are few times I don’t have something in the bag which permits me to get the shot I want. The IQ difference between a good zoom, I consider my DA* 16~50/2.8 to be a good zoom, and a prime is almost negligible.

Tom G

[sweetpapa]

After getting an FA35 prime, I neglected my 16-45 for a while.

But I'm falling in love with my 16-45mm all over again after wanting to shoot wide angle.

It proven to be very versatile and I don't need extremely small depth of field which is hard to shoot at the lower focal lengths.

[unfocused]

Cartier-Bresson did most of his best work with a standard 50mm (i.e. 35mm in APS-C terms).

[GeneV]

It can just be a different way of viewing the subject, when you move around instead of moving the zoom ring. I am often discovering something I like better about the new angle as well. I use a zoom when I am shooting some event where I can't move and a shot of the event from that particular angle is required.

As to quality, I really don't think there is a difference that matters to the vast majority of us. If you need to shoot a poster or a billboard with APS-C, you would see the difference. However, a P&S in decent light will get you an 8x10 or a laptop screen of your subject. It's my recurrent theme, but I think we obsess way to much about lens performance.

[RioRico]

It can just be a different way of viewing the subject, when you move around instead of moving the zoom ring. I am often discovering something I like better about the new angle as well. I use a zoom when I am shooting some event where I can't move and a shot of the event from that particular angle is required.

Indeed. With a camera zoom I can look at something, frame it, and shoot. With a prime I must move around to get the right framing. NOTE: I specified "camera zoom" because my Schneider Betavaron 50/125 enlarger zoom, on 32mm extension for non-macro shooting, also requires a great deal of dancing around to get the framing right. If I ever get a 30-70mm focusing helicoid, the Betavaron will become less exacting. Anyway, my oversimplification is that we use AF zooms to TAKE pictures and MF primes to MAKE pictures. I may have mentioned that before.

In a nearby thread asking suggestions for a compact travel kit, I cited ultra-minimalism: Kx+35/2.5, pretty equivalent to the 135 fixed-lens cam with 50/3.5 lens that I used long ago. Step close and it's a short tele; step back and it's just wide enough. Or on some K20D excursions I'll stick with a 28/2. Any of these (or any other fixed lens) forces me to look more closely, see more possibilities, etc. A zoom doesn't *force* laziness, but *allows* us to devote less effort to picture-making.

I'll again mention another favorite option: Enlarger lenses on bellows. These give me a great feeling of freedom. With the right focal length and extension, I can focus from beyond infinity to within very few inches, with a fine degree of control. My little Novoflex Noflexar 100/3.5 on my little Bellowscope just *feels* like a special general-purpose lens. Wide, not in AOV, but in focus range. And at just a few bucks each, it's easy to build a varied yet compact kit. 50mm for close macro; 75mm for portraits; 90-140mm for ... almost everything; 160-200mm to really stretch. And it's odd-looking enough that bystanders notice the rig, not what I'm aiming it at.

[Ahab]

Sorry, but I completely disagree. If both lens are stepped down, the sharpness for both lens should be very similar. But what about the bokeh, the barrel distortion, the CA, the contrast? There's a reason why lenses like the 200mm f2.8 exist. Calling it the same as a 60-250mm (An incredible zoom on its own by the way) at 200mm is like saying the 16-50mm f2.8 creates the same image as a FA 31mm f1.8 Limited at 31mm.

I'm not trying to be a Prime Lens fanboys, because I know a lot of zoom lenses that are great and they're versatile and some even looks cooler on a body (if you care about that). But I just can't stand people saying stuff like "oh my zoom at ___mm is just like a prime at ___mm. It's the exact same thing! LOL!!!" or "Don't waste your money on ___ prime lens when you can get the same quality for cheaper on ____ zoom lens." Well, no it isn't and it doesn't. Do you get the same picture? Sure, but the differences comes in the smaller details. Some people don't care for the details so much and that's fine and if they're trying to save a couple bucks, that's definitely okay, but it just annoys me sometimes when stuff like that is stated over and over again. There are images that primes can't do that zooms can, and that goes the same the other way around.

Thank you Eagle_Friends, I thought the 60-250 statement was absurd too. Having had both, I prefer the DA*200.