[domisplanet]

Hello everybody

This week I tested the Pentax d fa 28-105 on the Pentax K1 for wich it supposed to be the affordable standard zoom lens.
Maybe my expetations were a bit high... but ...to be honest, I was quiet disappointed about the image quality. Or lets say, the in my opinion terrible vignetting with open aperture at nearly all focal lengths.
I know that there is built in lens correction in the K1, but I am not a big fan of post processing and softwaresolutions for those kind of things. This should more be a solution for an older lens that somebody already may own.

Did somebody experienced the same or had I just a bad copy of this lens?

Any recommendations for an affordable alternative? What about the Tamron 28-75?

Thank you for you replies!

[Paul the Sunman]

Yes, the 28-105 vignettes a lot, but most people find it is not a big deal. I use the vignetting to frame the subject, or remove it with one click in LR. The IQ is still good in the corners. Removable vignetting is an acceptable price to pay for this excellent and convenient lens.

Here's an uncorrected/corrected comparison. For this subject, I actually prefer the uncorrected image, but the corrected version is fine.

K-1, 28mm and f/4.5, no corrections (left) and one-click profile correction in LR (right).

[rawr]

If a small degree of vignetting is one's only criticism of a lens, it's a good lens. And as has been pointed out, vignetting is easily corrected, in-camera automagically or on the computer, if it is a bother.

If it's any comfort, something like the Sigma 24-105 f4 Contemporary vignettes a LOT more on full-frame than the Pentax 28-105 does.

[UncleVanya]

What do you use to process? If you have never tried it take a shot at DXO Optics Pro and use the Smart Lighting and lens profiles - that will probably allow you easy fix without problems. As for vignetting - there are a lot of sources out there that will tell you this about many current lenses so you can at least know before you buy anything else. The Sigma 24-60 was recently discussed as a light alternative to the 24-70 variants, but it may not be sharp enough from a few reports I saw.

[Rondec]

You'll get some vignetting with the Tamron 28-75 f2.8 too. I wouldn't worry about it -- just fix it in post if it bothers you.

In the end, you probably will need to spend a little bit more or deal with the flaws of what you can afford.

[HopelessTogger]

How about the Sigma 2.8/24-70 EX DG Macro?

[domisplanet]

Thank you for your replies! I just switched to full frame dslr so I am wodering abit aubout this issue.
I agree with you, the lens is really sharp and the colours are nice!

I nerver had noticable vignetting on film, why is it a problem on full frame digital?
Of course I made the test shots with apperture settings I probably may never use... but still...

@Paul, thank you for the sample images. I agree with you, in this case I like the uncorrected image more aswell.

---------- Post added 10-15-16 at 10:52 PM ----------

@ Hopless Togger, as far as I know there is a compatibility issue with this lens. But yes this would be a good option.

[lennyl]

How about the Sigma 2.8/24-70 EX DG Macro?

Sigma 24-70/2,8 IF EX DG HSM, 411euro, NEW, in sale in our town :-)...without microadjustment corections, sharp from f2,8, perfect focus for all distance and focal length, at f11 sharp from cornet to corner. I'm happy.

31mm, f13, 20sec, ISO 200 with VF ND1000 and ND8soft
http://www.imagehosting.cz/images/imgp5611.jpg

24mm, f3,2, 13sec, ISO 100
http://www.imagehosting.cz/images/imgp6834.jpg

24mm, f16, 1/320sec, ISO 200
http://www.imagehosting.cz/images/imgp63msm.jpg

70mm, f2,8, 1/640sec, ISO 100 with Sigma DG Wide cpl
http://www.imagehosting.cz/images/imgp58rzr.jpg

27mm, f11, 1/13sec, ISO 100 with ND8soft
http://www.imagehosting.cz/images/imgp8860.jpg

24mm, f16, 3sec, ISO 100 with Sigma DG Wide cpl
http://www.imagehosting.cz/images/imgp3423.jpg

60mm, f13, 0,8sec, ISO 100 with Sigma DG Wide cpl
http://www.imagehosting.cz/?v=imgp3447.jpg

[Paul the Sunman]

I nerver had noticable vignetting on film, why is it a problem on full frame digital?

I'm not sure that's the case, but I can think of a couple of possible contributing factors.

First, on film, you may have been using prime lenses more, and it is easier to design those to minimize vignetting (apart from ultra-wides).

Second, the design of zooms involves a whole basket of compromises and balances. Things like size, weight, as well as sharpness, coma, flare, contrast, aberrations, ... and vignetting ... all at various focal lengths. In the digital age, the optimum balance might be different than on film. Of all the aberrations, vignetting is easiest to fix in post processing, so perhaps it's the one modern lens designers let slip a bit to buy themselves room to improve the others.

Overall, from what I've seen, the new Pentax zooms (especially the "in-house" ones, the DFA 28-105 and DFA* 70-200) more than match up against anything comparable from the film era.

[i_trax]

on the budget on the used market
Tamron LD XR Di SP 28-75 2.8 macro ( I purchased for ~AU$200)
Sigma 28-70 2.8 EX DG non HSM with the case ( I purchased for ~ AU$85 )
+ prime DA 40 2.8 Limited or DA 40 2.8 XS both excellent and can buy used for under AU$200

[ffking]

'm not sure that's the case, but I can think of a couple of possible contributing factors.

First, on film, you may have been using prime lenses more, and it is easier to design those to minimize vignetting (apart from ultra-wides).

Second, the design of zooms involves a whole basket of compromises and balances. Things like size, weight, as well as sharpness, coma, flare, contrast, aberrations, ... and vignetting ... all at various focal lengths. In the digital age, the optimum balance might be different than on film. Of all the aberrations, vignetting is easiest to fix in post processing, so perhaps it's the one modern lens designers let slip a bit to buy themselves room to improve the others.

I'm sure you're right - but I also think that in the film days we were more likely to accept the characteristics of the system as inevitable and work them to our advantage rather than see them as defects - the differences between the way film records an image and the way the eye/brain do are much greater than with digital and using those differences was second nature - so a bit of that rubbed off on lens characteristics as well, I'm sure.

[UncleVanya]

Film - specifically print film - typically has a wider lattitude than digital sensors so subtle differences in exposure are possibly masked.

[HopelessTogger]

Sigma 24-70/2,8 IF EX DG HSM, 411euro, NEW, in sale in our town :-)...without microadjustment corections, sharp from f2,8, perfect focus for all distance and focal length, at f11 sharp from cornet to corner. I'm happy.

31mm, f13, 20sec, ISO 200 with VF ND1000 and ND8soft
http://www.imagehosting.cz/images/imgp5611.jpg

24mm, f3,2, 13sec, ISO 100
http://www.imagehosting.cz/images/imgp6834.jpg

24mm, f16, 1/320sec, ISO 200
http://www.imagehosting.cz/images/imgp63msm.jpg

70mm, f2,8, 1/640sec, ISO 100 with Sigma DG Wide cpl
http://www.imagehosting.cz/images/imgp58rzr.jpg

27mm, f11, 1/13sec, ISO 100 with ND8soft
http://www.imagehosting.cz/images/imgp8860.jpg

24mm, f16, 3sec, ISO 100 with Sigma DG Wide cpl
http://www.imagehosting.cz/images/imgp3423.jpg

60mm, f13, 0,8sec, ISO 100 with Sigma DG Wide cpl
imgp3447.jpg at ImageHosting.cz - Hosting pro tvoje fotky a obrazky

Thank you. I've been looking at the options for a 2.8/24-70 standard zoom for the K-1 and I just cannot bring myself to accept the price (and quality, reviews are mixed) for the Pentax D-FA 2.8/24-70. It's £1149 in the UK, whereas the same Tamron lens for Nikon and Canon is around £700. The Sigma can be had for around £500. That's a big difference.

[lennyl]

HopelessTogger:
one friend with K-1 bought the DFA24-70WR (1.130euro) and we tested DFA24-70 vs my Sigma 24-70/2,8 IF EX DG HSM.

Both lenses has absolutely quite focusing (HSM and SDM), the optical quality were both lenses the nearly same, but Pentax focuses less accurately - of course we tried to switch cross the lenses on two K-1.
Purchase of Sigma is my best deal in life (411euro).

[Paul the Sunman]

Is the Sigma 24-70 f/2.8 still available for K-mount? I don't see it listed new anywhere. B&H list it as "no longer available".