Fast 28-30mm lens comparison


sorted78

Link Posted 24/04/2011 - 23:00
Having recently rationalised my lens collection, I ended up with some funds burning a hole in my PayPal balance and, in the way of LBA, now have a range of lenses covering a fast APS-C 'normal' focal length.

Most I have bought for a specific reason or application (or a price too good to pass up), but in an idle moment yesterday, while making sure my kids didn't drown themselves (or each other) in the paddling pool, I did a quick comparison.

The lenses:
- Sigma 24-70mm f/2.8 @28mm (to give a comparison with a decent zoom)
- Sigma 30mm f/1.4 (a favourite for low light and portraiture)
- Vivitar (Komine) 28mm f/2.0 CF (one of my first primes and very good value for money)
- Pentax SMC 28mm f/2.0 (K series developed in cooperation with Carl Zeiss - I'm a big fan of the K series lenses and had always wanted a copy of this one)
- Pentax FA 28/2.8 (modern AF Pentax prime)

What I looked for:
- Sharpness
- Out of focus rendering
- Colour and contrast

The process:
I took 3 images with each lens, which were taken as JPGs straight out of the K-5:
- Close up of some apple blossom wide open (sharpness and tricky bokeh on the shed in the background. This isn't a fair comparison as the lenses have different maximum apertures, but the other two images should redress this a bit)
- Same close up of apple blossom at f/8 (sharpness and general quality stopped down)
- General landscape shot at f/8 (sharpness, contrast and colour rendering)

The camera was tripod mounted, using the 2s self-timer at 100 ISO. I focussed manually using live view to verify the focus - there was slight movement of the flowers in the breeze, but I think that the focus is as good as I could have got it in each case.

I haven't done any PP on the images here, mainly because I wanted to make it as fair a test as possible (assuming that the camera does roughly same processing on each one) and also because it's not something I'm very experienced at yet. Also it would have taken much longer, as I can easily script resizing renaming and cropping!

Disclaimer
I'm not what I think is referred to on the other forum as a 'measurebator'; test charts, MTF figures and pixel peeping isn't my cup of tea. I thought that the results here were interesting and I've learned quite a lot from doing this, my results are pretty subjective/empirical and any constructive input is welcome!


Close up, wide open

Sigma 24-70mm f/2.8 (~28mm at f/2.8 )


100% crop


Sigma 30mm f/1.4 (at f/1.4 )


100% crop


Vivitar (Komine) 28mm f/2.0 (at f/2.0 )


100% crop


Pentax SMC K 28mm f/2.0 (at f/2.0 )


100% crop


Pentax SMC FA 28mm f/2.8 (at f/2.8 )


100% crop




Close up, f/8
Sigma 24-70mm f/2.8 (~28mm at f/8 )


100% crop


Sigma 30mm f/1.4 (at f/8 )


100% crop


Vivitar (Komine) 28mm f/2.0 (at f/8 )


100% crop


Pentax SMC K 28mm f/2.0 (at f/8 )


100% crop


Pentax SMC FA 28mm f/2.8 (at f/8 )


100% crop





Landscape, f/8
Sigma 24-70mm f/2.8 (~28mm at f/8 )


100% crop


Sigma 30mm f/1.4 (at f/8 )


100% crop


Vivitar (Komine) 28mm f/2.0 (at f/8 )


100% crop


Pentax SMC K 28mm f/2.0 (at f/8 )


100% crop


Pentax SMC FA 28mm f/2.8 (at f/8 )


100% crop




Conclusions
It's very subjective, but I think they're all pretty good! The Vivtar is spectacular value for money, but the Pentax K and Sigma lenses have better contrast and bokeh that I find more pleasing.

The Sigma 30/1.4 is impressively sharp side open and has really smooth bokeh.

One of the real surprises is how good the Sigma 24-70 is; it's sharp and has surprisingly good rendering for a zoom.

However, there is something special about the colours from the Pentax lenses and I really like the smoothness and subtlety of the bokeh from the K28/2.

Dangermouse

Link Posted 24/04/2011 - 23:35
It's interesting to see that the K28/2 seems to have similar properties to the K28/3.5. Both are sharp wide open, but the f2 naturally opens wider.

I have a handful of K lenses (28/3.5, 55/1.8, 120/2.8, 28-50/3.5-4.5 and 85-210/4.5), none of them show their age although the zooms could do with professional attention. One has a blob of fungus and the other rather more dust than is healthy as a result of my cleaning fungus from it!
Matt

Shooting the Welsh Wilderness with K-m, KX, MX, ME Super and assorted lenses.

Frogfish

Link Posted 25/04/2011 - 11:13
I think the slight breeze may have affected focus in some cases - impossible to control using the 2 second timer but a very nice comparison test - thanks for taking the time to shoot, edit and publish it !
http://frogfish.smugmug.com/ Pentax. Pentax DA*300/4, Cosina 55/1.2, Lens Baby Composer Pro & Edge 80, AFA x1.7, Metz 50 af1.
Nikon. D800. D600. Sigma 500/4.5, Nikon 300/2.8 VRII, Sigma 120-300/2.8, Zeiss Distagon ZF2 21/2.8, Zeiss Distagon ZF2 35/2.0, Sigma 50/1.4, Nikkor 85/1.8, Nikon TC20EIII, Nikon TC14EII, Kenko x1.4, Sigma 2.0

Algernon

Link Posted 25/04/2011 - 11:50
It's very difficult to compare 28mm lenses (unless you have a really bad one). The 100% crops don't look impressive, but that may be because of the amount of pixels on a K-5, obviously a 100% crop from a K-10D would look better.

The Sigma 30mm and Vivitar 28mm f/2 are known to be sharp in the center and poor at the edge.

From the wide views I would say the Pentax SMC FA 28mm f/2.8 (at f/8 ) looks about the best, but I haven't seen the full sized shots. The shed and fence on the right look really sharp and it's picked out the trees in the background with good contrast. The others look to be struggling there. It would probably make an excellent landscape lens. The Vivitar and two Sigmas seem to be struggling with the distant details.

The Pentax SMC K 28mm f/2.0 looks impressive and very similar to the FA.
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi

johnwhit

Link Posted 25/04/2011 - 12:16
Algernon wrote:


From the wide views I would say the Pentax SMC FA 28mm f/2.8 (at f/8 ) looks about the best, but I haven't seen the full sized shots.

Cracking lens, but a little soft wide open, vignetts a bit at f/2.8 as well. Still, I wouldn't part with it

John
PPG link

In LBA hiatus.
Last Edited by johnwhit on 25/04/2011 - 12:17
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