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cyberjunkie · 06-09-2014, 03:00 AM

I am sure that the matter (as per post title) has been discussed before. After giving it a thought, i came to the conclusion that the subject could interest many of us, so i decided to go specific, and ask your opinion about the availability of high quality alternatives to the f/2.8 zooms which dominate the prosumer market.
First let's try to explain what i'm thinking.
With film cameras you had the need for fast lenses, to avoid camera shake in low light, or at least to avoid using extremely grainy super-fast films.
Recently the performance of current digital sensors allows to shoot at very high ISO values, without too badly affecting the quality of the image.
It is true that fast lenses can be used to isolate the subject and blur the background, but personally i prefer to use very fast primes to achieve that effect (with even better results, cause i have primes which are faster than f/2.8). Basically, a 50mm "normal" from the film days would do...
Unfortunately fast primes fill up the bag rather quickly, if a good range of focals is needed.
In my case, size and weight are even more important, cause >90% of my pictures can be broadly defined as "travel photography".
Until very recently, most of my lenses consisted in manual focus primes. Then i moved abroad, and i could restart traveling, so i realized that the best outfit for travel photography consists in a few high-quality fast zooms.
After buying a couple of new (second hand

) zooms, i'm not so sure anymore.
F/2.8 zooms are heavy, or at least quite bulky!
My doubts are reinforced by my recent experience: i shot plenty of very low light pictures, using two old zooms with average max aperture, from the old days of film cameras!
I would be OK with them, but one is plagued by fringing, the other isn't very sharp (at least not below F/8).

With all that in mind, i asked myself a simple question: are the zooms currently marketed in PK-AF mount, in tune with the new reality (sensors/electronics with good high-ISO performance)?
My knowledge of new digital equipments is limited, from what i found thirds party offerings didn't keep up very well with the changing reality.
The high-quality zooms are still the f/2.8 ones, like in the analog days.
Pentax seems to cope a little better with the new reality, but personally i find that the "originals" of higher quality are overpriced.
At a general level, not just brand specific, don't you think there is a lack of high-quality prosumer zooms, with slightly reduced max aperture?
F/3.5 or F/4 zooms would be smaller and definitely cheaper, and probably could be made with top level IQ, even wide-open!

Going more practical and less "philosophical", any suggestion about zooms already available second-hand, which could fall in the category of "high-quality/medium-speed"?
I am more interested in third-party brands, i found that Pentax kit/amateur lenses are quite cheap, but the high-quality ones can be REALLY expensive. Out of reach for me.
Personally i am not very interested in high-cost stuff, and i try to stick to a simple rule: allow myself to try new lenses, but at the same time try to avoid stuff that nobody wants, or pay more than what can be easily gotten reselling the item

At the moment i am considering an AF zoom in the 70-200/80-210mm range, or maybe also a 100-300 or 150-400.
I didn't check very well, but i couldn't find something equivalent to the fixed apertures zooms from the early days of Pentax lenses with electric contacts.
For example like the Pentax-A 70-210mm F/4 i own (or like the Pentax-A 35-105mm F/3.5, different zoom range but still an outstanding zoom with fixed max aperture!).

I am open to specific suggestion, but i'm even more curious about what you think, on a more general level.

ciao

Paolo

Last edited by cyberjunkie; 06-09-2014 at 04:12 AM.

Giklab · 06-09-2014, 03:10 AM

Recently, I took some photos at a concert, using my 18-135 and a 400 f/6.3 - images from the latter only have me as a problem, since I can't focus very well yet.

There is no need for fast lenses anymore if all you want is a shot to document your experience. However, there is another downside to high ISO settings other than noise - the DR and colour reproduction take a huge hit. Check out DxOMark for their DR graphs. And find Matt Granger's videos on Youtube about High ISOs, the recent one and the one from the 'Educating Tina' series.

Mazhe · 06-09-2014, 04:24 AM

Oh, you found a sensor with high iso performance? That would be a first

cyberjunkie · 06-09-2014, 04:35 AM

Originally posted by Mazhe

Oh, you found a sensor with high iso performance? That would be a first

Probably i should word it in a different way:
not-so-terrible digital noise at high-ISO

Just try to remember what you got with high-sensitvity film, especially diapositive!

cheers

P

reeftool · 06-09-2014, 05:44 AM

The IQ of high ISO shots has improved a lot with the recent sensors but the noise is still there and having some sort of noise removal software is essential. The K5 exhibits noise even at ISO 100 which my K10D didn't. The K5 shots clean up very well in Lightroom, even up to ISO 12800.

The lens issue is a different matter. Faster lenses are generally a higher quality lens. They have to be if they are to be useful a wide open apertures which is why most people buy them in the first place. In the film era, there were other reasons for a faster lens and that was manual focusing. There were a lot of "fast" lenses that weren't too great wide open but needed a brighter viewfinder to manually focus. I own a few third party f/2.8 MF lenses which are essentially useless at f/2.8. Digital era f/2.8 and faster lenses tend to be pretty high quality. I also own some "slow" glass which have poor IQ wide open also at apertures of f/4 or more and are only usable from f/8-f/11. Fast lenses are always a benefit when manual focusing, even if you aren't shooting wide open. A brighter viewfinder also benefits auto focus cameras in locking focus quickly.

Pentax glass through the years has been pretty good. My M135/3.5 is sharp through the whole aperture range. The F 35-70, an old film era zoom is good as is the DA 16-45. Slower lenses but very high IQ. Pentax is taking some flak for the relatively slow DA 20-40, the argument being that a "quality" lens at that price point should be f/2.8 throughout the zoom range. Evidently, the market isn't ready to accept a high end lens that at least f/2.8 throughout the zoom range.

**jatrax** · 06-09-2014, 05:56 AM

I find the reliance on higher ISO to be problematic. For snapshots or 'record' shots, yes of course, the newer sensors are amazing. But I find it very difficult to get a salable image at ISO 800 with the K-3 or ISO 400 with the K-5. Not that it cannot be done, just difficult and requiring more work in post processing than I prefer. And even with lots of noise reduction work the exposure must be very good for an image to come out well. I rarely shoot over ISO 200 with K-5 or ISO 400 with K-3. So not really any different than film speeds. Add on a CPL and that f/2.8 lens is still very attractive to me.

But I agree on more high quality zooms. I would really love a 16-85 f/4 with IQ of * level. Or the rumored 150-450ish zoom provided it is fast enough (maybe f/4-5.6?) and has IQ similar to *60-250

Kozlok · 06-09-2014, 06:51 AM

The Pentax 18-135 is a great travel lens. I put that and a Sigma 30/1.4 in the bag as my travel solution. If you don't need WR, the Sigma 17-70 is a bit nicer and a bit faster, but less range.

jimr-pdx · 06-09-2014, 07:27 AM

Depth of field will be a big deal for many regardless of sensor capabilities - but I agree with you, a smaller / lighter lens will get more use in my bag. Despite that I really liked the Tamron 28-75 when it was with me

the copy I had was quite nice.

**Pål Jensen** · 06-09-2014, 07:43 AM

Originally posted by jatrax

I find the reliance on higher ISO to be problematic. For snapshots or 'record' shots, yes of course, the newer sensors are amazing. But I find it very difficult to get a salable image at ISO 800 with the K-3 or ISO 400 with the K-5. Not that it cannot be done, just difficult and requiring more work in post processing than I prefer. And even with lots of noise reduction work the exposure must be very good for an image to come out well. I rarely shoot over ISO 200 with K-5 or ISO 400 with K-3. So not really any different than film speeds. Add on a CPL and that f/2.8 lens is still very attractive to me.

Most wildlife photographers (including Frans Lanting) use their super telephotos at small aperture (like F:8) and boost the ISO significantly even with APS cameras. The slight gain in noise is not visible for any real life usage of the images (as opposed to pixel peeping) and is well worth the extra chance of getting the shot - getting enough DOF and/or helping slight focusing errors.
Even the K-7 show virtually no noise at 400ISO and even a cropped (40%) 1000 ISO shot is perfectly saleable even as a large print....

First one shot with FA* 200/4 at F:4 1000ISO, K7 no noise reduction. 40% crop

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