[mcgregni]

Once you chop the size of the image down to that for the KP, I guess that's right...... My maths is not that good , I'll take your word for it!

I think the reality is that very few people would actually need such resolution..... Only those who will order large physical prints (bigger than A3 ...?-), or still need to crop in even more than than aps-c size. The vast majority of us frankly don't need more than a K7 or K5 resolution.

[08amczb]

Many of you compared the DFA28-105 to primes (and some was arguing there are no modern primes for Pentax).

Someone could post images with 100% crops from the 28-105@31mm, F5.6 and from the FA31@F5.6. The same with FA*24, DA*55, FA77 and DFA100? From when I using primes only a few pro zooms produce really nice images for my eyes.

[awscreo]

I challenge anyone to find obvious optical flaws in these photos: DFA 28-105 | Flickr
All taken with 28-105. It's an amazing lens, and hits way above it's price point.

[pentageek]

The challenge is void - no reference shots taken with Limiteds Nice photos, BTW.

[rogerstg]

I challenge anyone to find obvious optical flaws in these photos: DFA 28-105 | Flickr
All taken with 28-105. It's an amazing lens, and hits way above it's price point.

Awesome shots. Regarding the lens; I especially like how it handled shooting into the sun.

[awscreo]

The challenge is void - no reference shots taken with Limiteds Nice photos, BTW.

That's one thing I will fix one day the 77 1.8 is of particular interest, looks like a marvelous piece of optical engineering!

---------- Post added 07-18-18 at 12:23 PM ----------

Awesome shots. Regarding the lens; I especially like how it handled shooting into the sun.

Yup, it handles flare really well. And it's very sharp corner to corner stopped down, which I tend to do all the time when shooting anything but portraits.

[BigMackCam]

Someone could post images with 100% crops from the 28-105@31mm, F5.6 and from the FA31@F5.6. The same with FA*24, DA*55, FA77 and DFA100? From when I using primes only a few pro zooms produce really nice images for my eyes.

If someone takes you up on that, I'll be as interested as you to see the results

However...

Who actually views a final image at 100% reproduction, 60cm from their computer screen? That's right, no-one but us photographers.

At normal reproduction sizes and viewing distances, the rendering of a lens is going to be far, far more important than critical sharpness at 100% reproduction. I mentioned in an earlier reply that my best lens overall is probably my Sony Zeiss 24-70 f/2.8... yet, there are times where the rendering of one of my lowly 1970s Helios-44-2 lenses will suit a shot better. And, at normal reproduction sizes, with relevant post-processing adjustments, you won't care about the difference in resolution between the two. You'll just find that you prefer one image to the other because it looks a bit nicer

While we're on that subject, what is it that you feel defines the performance of one lens being better than another? Because that's a very subjective thing. Is it resolution? Low distortion characteristics? Level of chromatic aberrations? Contrast? Colour reproduction? Out-of-focus rendering (and if so, what's your preference)?

If you answered resolution - i.e. MTF - then the D FA28-105, being a very modern and high performance lens designed to match the K-1 well, actually outclasses some of the classic primes at various apertures. It does awfully well on contrast, colour repro, and level of chromatic aberrations too - at least, if we believe the various reviews and the reports from our users. Where it may not perform so well is distortion... It's pretty much impossible to cover this sort of focal length range in one lens and not have some degree of distortion at one or both ends of that range, and possibly in between.

But perhaps the biggest difference you're likely to notice with lenses compared side-by-side, is the quality of out-of-focus rendering. It's one reason why primes such as the FA31, 43 and 77 are so revered. Related to that, all three of those lenses are much faster than the D FA28-105, so they'll produce greater subject to background separation. And that's a big benefit... but only if you need it. Some people don't, or they're prepared to trade that capability for the convenience of one nice, sharp lens that renders well, at a slower and variable set of apertures across a wide focal length range...

---

Last edited by BigMackCam; 07-18-2018 at 12:53 PM.

[mcgregni]

Here's one where I was trying to show the close focus and bokeh ….both things that surprised me when I first got the D FA28-105.



I don't know many f3.5-5.6 zooms that can make photos like that.

[mikesbike]

Thanks for the answares.

I'am supprised how many of us would like to walkaround with a FF digital K-1, I do not want (and I don't have one). I use my KP with my 18-135 for walkaround, I add the DA15 when I need a wider lens also. My other walkaround setup is the PZ-1p with the three FA limiteds.

This is very good information. Now it is clear that you know what your 3 FA Limiteds are like used with a FF body compared with APS-C. I am with you all the way- my walkaround FF outfit involves the excellent PZ-1p or the MZ-S, in my case the Pentax FA 35mm f/2, FA 43mm f/1.9 and FA 77mm f/1.8 Limiteds, and the Tokina 28-70mm ATX f/2.6-2.8 Pro II zoom lens. I also have a couple of Pentax FA 28-105mm lenses that are much lighter, as well as the very good FA 28-70mm f/4.

Of course, the answer to the question of prime vs. zoom lens is obvious. Each one can do what the other cannot. There are no f/1.8 zoom lenses, and if there were, the performance wide open would not be comparable. OTOH, a zoom lens can do what no prime can- instantly change FL. So with a zoom lens one can often get a shot that would be missed with a combo of prime lenses. It is simply more versatile, and these days there are numerous zooms that can deliver excellent IQ.

Nothing wrong at all with your way of doing things. Your logic is very good. So why would anyone get a K-1 and the D-FA 28-105mm instead of what you are doing? Well, if you are out and about all day with your PZ-1p outfit, and come across a situation where the flexibility of a zoom lens would be very useful, or even necessary, and since you know what your PZ-1p outfit can do with your FA Limited lenses that would not be possible with your APS-C KP, then your question is self-answered.

Although a film SLR has is own virtues, the virtues of a modern DSLR like the K-1 far out-weigh those. No contest these days when it comes to high resolution low-light/low noise (grain) performance. Not to mention the convenience and effectiveness of processing, and if you do the film thing often, over time the cost of that would pay for a K-1.

As for me, I am more than satisfied with what I can get with my APS-C bodies, especially the KP. I rarely do film anymore. I just keep an eye on the development of the Pentax FF line to see if at what point I might jump in for the reasons above.

[awscreo]

This is very good information. Now it is clear that you know what your 3 FA Limiteds are like used with a FF body compared with APS-C. I am with you all the way- my walkaround FF outfit involves the excellent PZ-1p or the MZ-S, in my case the Pentax FA 35mm f/2, FA 43mm f/1.9 and FA 77mm f/1.8 Limiteds, and the Tokina 28-70mm ATX f/2.6-2.8 Pro II zoom lens. I also have a couple of Pentax FA 28-105mm lenses that are much lighter, as well as the very good FA 28-70mm f/4.

Of course, the answer to the question of prime vs. zoom lens is obvious. Each one can do what the other cannot. There are no f/1.8 zoom lenses, and if there were, the performance wide open would not be comparable. OTOH, a zoom lens can do what no prime can- instantly change FL. So with a zoom lens one can often get a shot that would be missed with a combo of prime lenses. It is simply more versatile, and these days there are numerous zooms that can deliver excellent IQ.

Nothing wrong at all with your way of doing things. Your logic is very good. So why would anyone get a K-1 and the D-FA 28-105mm instead of what you are doing? Well, if you are out and about all day with your PZ-1p outfit, and come across a situation where the flexibility of a zoom lens would be very useful, or even necessary, and since you know what your PZ-1p outfit can do with your FA Limited lenses that would not be possible with your APS-C KP, then your question is self-answered.

Although a film SLR has is own virtues, the virtues of a modern DSLR like the K-1 far out-weigh those. No contest these days when it comes to high resolution low-light/low noise (grain) performance. Not to mention the convenience and effectiveness of processing, and if you do the film thing often, over time the cost of that would pay for a K-1.

As for me, I am more than satisfied with what I can get with my APS-C bodies, especially the KP. I rarely do film anymore. I just keep an eye on the development of the Pentax FF line to see if at what point I might jump in for the reasons above.

Two Sigma zooms are 1.8 and both highly regarded as far as I know

[Ronald Oakes]

I challenge anyone to find obvious optical flaws in these photos: DFA 28-105 | Flickr
All taken with 28-105. It's an amazing lens, and hits way above it's price point.

Very Nice ! Thanks for posting this

[clackers]

Many of you compared the DFA28-105 to primes (and some was arguing there are no modern primes for Pentax).

Someone could post images with 100% crops from the 28-105@31mm, F5.6 and from the FA31@F5.6. The same with FA*24, DA*55, FA77 and DFA100? From when I using primes only a few pro zooms produce really nice images for my eyes.

IIRC, Ben, TheEnglishPhotographer, I think his handle is, showed that the FA31, FA20-35, DFA28-105 and 35mm Sigma Art all took pretty much the same pics of a particular rural building scene at f8, for instance.

There's a thread about it somewhere.

[awscreo]

Very Nice ! Thanks for posting this

Thank you! I have a ton more photos taken with the lens, I take it on every trip I go to, but I only uploaded them to Facebook. I think this lens is a perfect one lens setup for travel, but it's also very capable for more methodical and serious work imo.

[SSGGeezer]

Even though I only own APS-C, I wanted to get one that I saw in the forums for sale but was too late. WR, Nice focal range, modern coatings and great IQ.

The real question should be, why wouldn't you buy a DFA 28-105? It is a brilliant length zoom in older manual glass that still performs well, with modernization, there is no reason not to buy one if the opportunity arises.

[RGlasel]

I don't know many f3.5-5.6 zooms that can make photos like that.

The DA 18-135.


The resemblances between the two lenses are striking, to cover the FF image circle, the D-FA 28-105 gives up reach on the telephoto end, but they are very close in weight, diameter and length. Really, it is all about wanting to use the K-1 instead of an APS-C Pentax camera, for reasons that have everything to do with the camera and nothing to do with the lenses. If a K-1 owner wants to take uncropped pictures with a zoom lens that costs less than $1000, weighs less than half a kilogram and has a modern AF motor, the D-FA 28-105 is the only option, it doesn't matter what kind of pictures it takes.