HD Pentax D FA 28-105


MrB

Link Posted 13/09/2016 - 17:08
McGregNi wrote:

Philip, some good examples at different focal lengths, I think demonstrating that it's a very consistent lens over its range. That close-up at 105mm is good and sharp, and I'm also very pleased with things that close, and with the excellent minimum focus distance as well.

What's happened to the K-S2 ?? It's not ready for relegation yet, surely?! I can understand you might have fancied a go at Pixelshift however .....

Hello Nigel. The K-S2 is a great camera but the K-70 appears to have many of the good features of both the K-S2 and the K-3 series bodies and at a good value price. So I decided to trade in the K-S2 for the K-70. I suppose its all part of the gear addiction syndrome really, and probably an Everest type thing (no, not about double-glazing) - I went for it because it's there and I had some spare cash!

The lens is as pleasing as I thought it might be. For me it covers the focal lengths that I like on APS-C, and I have no plans or intention of getting the K-1. It is similar in size and action to the DA 18-135 and that can give pleasing results, although it can tend to fall off at the edges and corners. I'm hoping I'm correct to expect that the 28-105, being a 135 format lens, will always be presenting the best quality part of the image circle over the smaller rectangle of the APS-C sensor?

Cheers.
Philip

JAK

Link Posted 13/09/2016 - 20:32
MrB wrote:
[quote:3496ace15f="McGregNi"]
Being a 135 format lens, will always be presenting the best quality part of the image circle over the smaller rectangle of the APS-C sensor?

It's actually pretty good for resolution right to the edges and doesn't seem to suffer with chromatic aberration, at least not in the photos I've taken with it so far.
This is another complete full frame image from last Sunday at 34mm, f5.6:


There might be the slightest single pixel width hint of aberration at the edges on the white fence on the left (100% crop.) Certainly nothing to worry about.:


John K

McGregNi

Link Posted 13/09/2016 - 20:54
It is fairly universally reported to hold up very well at the 'Full Frame' edges, so I bought with confidence that it would be equally dependable on a future K1 (or successor) for me,

You're right about the usefulness on aps-c of that 28-105 range, Philip. The 18-135mm is not supposed to be quite as good, from the reviews and user reports I checked. I decided to allow the new lens to pair up with the 18-55 for now, making a good weather sealed twosome, covering most needs.

Its clear enough to me though, having worked on a fair number of shots so far with the new 28-105, that its in a very different class ..... a 'bag of primes' ?? Not sure about that, bufrom itt I'd say I'm seeing 'prime like' IQ coming out of the K7 whn using this lens, and it sure has given the old camera a new lease of life!

I've had no issues at all either with abberations or fringing John ... very pleased in that respect.

Here's a couple of my favourites so far ....









My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver
Last Edited by McGregNi on 13/09/2016 - 20:58

JAK

Link Posted 13/09/2016 - 22:04
Sorry to be slightly off topic talking about the 28-105. You mention using the 18-55 to pair with the 28-105. While that's fine on APSC it won't help much for full frame. I actually purchased via the forum here an old FA-J 18-35 that was the kit lens for the IstD. But this is a full frame lens and 18mm on FF is pretty wide. The lens is only 200 grams, the same weight as the DAL 18-55. So if someone is reading this and thinks around 1200 is a bit expensive for the 15-30, then the 18-35 is a very viable alternative at a small fraction of the cost of the newer lens besides being much lighter to carry.
A full frame image from it? Well here @ 18mm, 1/40" @ f5 (almost wide open) :


Cost of 18-35 lens? approx 75
vs. cost of 15-30? at least approx 1200
I'm not sure the newer lens is 16 times better and the 18-35 takes the common 67mm screw in filters whereas the 15-30 doesn't.
John K

MrB

Link Posted 13/09/2016 - 22:36
A few more APS-C images from Maidenhead:

6. The road bridge at 40mm:



7. Riverside path under the bridge at 28mm:



8. Brunel's railway bridge at 28mm:



9. Private road but public footpath at 34mm:



Cheers.
Philip

JAK

Link Posted 15/09/2016 - 19:26
Something different with the lens late this afternoon


Autumn Harvest

The vignetting seems inherent in the lens at 105mm wide open (f5.6)
John K

McGregNi

Link Posted 15/09/2016 - 21:20
That's what I read is the main issue on FF, and it is interesting to see it here .... really a very obvious effect. However I'd assume its fairly simple to deal with on the computer .... vignetting controls are simple I think , and if the effect is the same in each corner then a single slider input should deal with it all at once. John, does the camera have vignetting reduction in the JPEG processing options?

Nice also to see those extra views of the river and bridge Philip ...
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver

JAK

Link Posted 15/09/2016 - 22:05
The camera is supposed to correct things like that with its jpegs from own brand lenses used within their limitations, eg, not for an APSC lens used at FF, and barrel/pincushion distortion if that option is tuned on (that isn't presently.) This led me to wonder, what is the in camera jpeg like to answer your question.

What do you think?


In camera jpeg reduced to 1000 pix for the forum.

The previous upload was from the dng file converted in PS Elements 11. That won't be aware of this lens.

I don't reckon the vignetting is so pronounced in this camera processed jpeg, however I like having it in this particular image as it adds a sort of timeless quality to it.
I did experiment trying to remove it from the dng conversion but couldn't get an even result. Maybe a newer PS or Lightroom may be more refined and do a better job.... or use the in camera jpeg if it intrudes.

Update:
Tried developing the dng in camera and that does exhibit the vignetting.
John K
Last Edited by JAK on 15/09/2016 - 22:26

joostdh

Link Posted 15/09/2016 - 22:38
Vignetting is for me one of the less disturbing artefacts a lens can have. Softness or overt CA are much more annoying.
Pentax K-1| Pentax K-01 | D-FA 28-105mm | FA 28mm F2.8 | FA 35mm F2.0 | FA 43mm F1.9 Ltd | FA 50mm F1.4 | FA 50mm F2.8 Macro | FA* 85mm F1.4 | FA 100mm F2.8 Macro | DA* 200mm F2.8 | Pentax AF 540FGZ

McGregNi

Link Posted 16/09/2016 - 00:12
Yes, I wouldn't be too worried about it really. John, the camera JPEG looks a lot better, clearly it has mostly dealt with the vignetting quite effectively. AFAIK no third party software (LR / PS etc) can interpret and act on specific lens correction settings from the camera .... only Pentax Digital Camera Utility.
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver

JAK

Link Posted 16/09/2016 - 09:50
PDCU ? Isn't that written in 8 bit basic? It's just too slow to make it a serious everyday tool and lacks many of the options available in other programs.

Out of interest, in PDCU, with auto correct on it does sort out the vignette, with it turned off it returns.



Saved the PDCU conversion as a tif, modified in Elements and border/text added in Irfanview!
John K
Last Edited by JAK on 16/09/2016 - 10:13

smudge

Link Posted 16/09/2016 - 10:31
I have also had the feeling that the 28-105 tends to over expose. As an experiment I have just taken 3 shots of part of my garden using 3 different lenses on the K1. All were set to 50mm. The camera settings were unchanged - AV f5.6, ISO200, EC -0.3.

The first shot is with the FA 50


The next was with the Sigma 24-70


Then with the DFA 28-105



As you can see the 28-105 image is exposed differently from the others - particularly noticeable on the canvas awning.

I then tried the same experiment on the K5II, using the same lenses plus some APS-C 16-50, 17-70, 16-85. This time the exposure for all lenses was consistent - including the 28-105.

All images straight out of camera with no pp
Regards, Philip
Last Edited by smudge on 16/09/2016 - 10:44

johnriley

Link Posted 16/09/2016 - 11:35
What is noticeable is that the 28-105mm is sharper. Any difference in exposure is very small and the slightly lighter shot does take the muddiness out of the reds.
Best regards, John

DaveKitson

Link Posted 16/09/2016 - 11:44
smudge wrote:
I have also had the feeling that the 28-105 tends to over expose.

+1, I routinely use negative compensation with this lens on the K1.

That said, I find it an excellent lens for hiking or holidays (compact, low weight and good IQ).
dave k
My PBase: www.pbase.com/davekitson

JAK

Link Posted 23/09/2016 - 15:02
A couple of days ago I took some comparison shots. One with the new 28-105 and the other the FA 50mm f1.4 prime







Both were taken in program mode and the camera decided for both to shoot them at 1/800" @ f5.6 @ 100 ASA. No over-ride or anything.

It's pretty easy to work out which lens was used for each shot given the obvious exposure differences, yet both report the same setting!

I've emailed Ricoh and SRS to see if this is a common issue. If it is not I've requested my lens be replaced, if it is I'm going to request a refund as it is all to easy to forget to dial in underexposure and end up with an over exposed photograph. We're not talking about an old M lens having to press the green button, this is supposed to be the latest and the best and priced accordingly.
John K
Last Edited by JAK on 23/09/2016 - 15:07
Add a Comment
You must be registered or logged-in to comment.