Minolta 28-105mm RS on A900

[David Kilpatrick]

Just to confirm - I used this lens seriously for the last week, rarely changing to my 70-300mm SSM and only when situations demanded it switching to the 12-24mm Sigma. I've been working today on raw file processing, and it looks as if the 28-105mm is significantly better than any other wide-to-tele full frame zoom from the 1990s period (and also, better than the 24-105mm within its range). The only real issues could have been solved with more thought; I will never leave a UV filter for sunsets, as this produces a direct and clear reflection (not so visible in the finder) - the lens has a very flat front element.

I may have got hold of a good example and it's also just a touch softer than the 28-75mm f2.8, made up for by excellent even coverage and almost zero CA (a striking contrast to the CZ 16-80mm with its very sharply defined CA). Life has been easy doing today's file processing as the 12-24mm Sigma has zero CA when used as I do, stopped down around f8-11 on a tripod nearly all the time.



105mm, at f8, no CA or other correction needed - a hint of 'bokeh CA' is present but overall sharpness, luminosity, effectiveness of the petal lenshood (the deepest of all of them ever made in this style) - it works well.



A close-up wide open, at 85mm, minimum focus, ISO 400. Again, no CA to correct. Edges of the lettering as the blur sets in for differential focus stay clean.



28mm, stopped down 2/3rds of a stop from max aperture, to f4.5. Some slight softness to corners, some loss with depth of field to left hand side (focus on the far wall and window shutters here) but very good geometry, no CA present even on the bright edges of the chandelier and other details.

This lens has won its place now, it will be my standard lens for the A900.

David

[Dr. Harout]

Great and thanks for the info, David. This is quite important for us, regardless of using FF or APS-C.
I think it would be great to create a section for lens database here with strict regimen.
Thanks again.

[aster]

I may have got hold of a good example and it's also just a touch softer than the 28-75mm f2.8, made up for by excellent even coverage and almost zero CA (a striking contrast to the CZ 16-80mm with its very sharply defined CA). Life has been easy doing today's file processing as the 12-24mm Sigma has zero CA when used as I do, stopped down around f8-11 on a tripod nearly all the time.

Hi David,

Looks like you had very intersting scenes to photograph in the past week.
It's good to learn that you had less troublesome results from this particular lens and that it is definitely working for the A900. But I'm still trying to figure out what the CA from CZ 16-80 looks like. The photos I took with it during the daylight hours show no signs of it or am I missing something?

Could someone provide/upload a photo taken with CZ 16-80 which also has an abundance of significant Chromatic Aberration please, so that I see what it actually looks like?

Thanks
Yildiz

[Vidgamer]

I'm curious to know if the 28-105xi is of a similar design or not. I got one for SUPER cheap, and it takes pleasant photos, but it suffers a bit from excessive blooming wide open. It seems sharper stopped down like most lenses. Not sure that I'm happy with it yet, but I need more opportunities to use it. My main problem with it recently was using it on an overcast (?) day and it just wasn't fast enough, particularly when I tried a smaller aperture.

[David Kilpatrick]

Could someone provide/upload a photo taken with CZ 16-80 which also has an abundance of significant Chromatic Aberration please, so that I see what it actually looks like?

Thanks
Yildiz

Not without going back to some early shots - my current one is not bad, it still needs correction, but only shows strong CA in particular circumstances with branches against bright white sky etc. I can'f find any examples like that without diving into my raw file archive, but I can find an example on the 28-105mm which is about as bad as it gets, and a 'regular' example on the 16-80mm:

chromafringe16mmf4.jpg (19.04 KiB) Viewed 6401 times

This is at f4, the contrasts are not extreme and you can clearly see the well-defined (not fuzzy) magenta and green CA on opposite sides of light-dark transitions. This is corrected by a -30 MG adjustment in ACR.

This is a very bad example from the 28-105mm (but the 16-80mm can do this too depending on focus distance, conditions - like this, with extreme contrast).

Even then, corrections can remove it - -35MG and +20CY corrections plus Defringe All Edges in ACR:

The point of focus in the shot this is taken from - and it is a very tiny bit of a 24 megapixel frame at the extreme edge, and the only part of the shot showing the problem - was well forward of this detail.

It's a small area at the very top. Grave of poet/celtic-myth scholar Robert Graves at Deja in Mallorca.

David

[aster]

Thank you David,

Now, I know what to look for when I'm shooting contrasty objects against a bright sky, though I havent seen this in my photos as of yet.

Very interesting place in the last photo too. To find a fellow British poet's grave in Mallorca must be an emotional experience but I guess it was a place much-prefered by many famous artists in the duration of their lifetimes.

Yildiz

[bakubo]

Welcome back! It seems like I haven't seen you around the forums much lately. Were you travelling?

[David Kilpatrick]

It's only a week A quick holiday in the usual fashion (driving to all four corners of Mallorca and every bit between, but leaving some interesting mountain roads for a future expedition).

David

[Al_]

I use an A200 and I recently got a 28-105mm RS to replace a 24-85mm RS and have been pleasantly surprised by the quality of images. Nice to know that it'll work fine on the A900 if I ever get one.

[KevinBarrett]

Hello Al_ and welcome to the forum!

[Dr. Harout]

A welcome from me too Al_ .

[Al_]

Thanks all for the welcome. Some interesting and useful stuff here.

[sparaxis]

Sometimes I think we expect too much from "film era" full frame lenses. What we all tend to forget is the effective size of 35mm film is not 24 mm x 36 mm but something smaller due to the inevitable cropping that takes place in a slide mount or in the printer. This was often the excuse given for the less than 100% viewfinder coverage. Most of the slides I have scanned seem to be in mounts with an aperture of around 22.5 mm x 34 mm. Perhaps when designing challenging lenses like 28-105, 24-85 and 24-105 standard zooms the designers quietly accepted poor corners, knowing that most users would never actually use the corner of the image. It was only the hardcore do-it-yourselfer (like myself) that went to the trouble of printing the full frame, sometimes having to file out the negative carrier of an enlarger to achieve it. The worst lens I have is the 20mm f2.8 MD, that actually has rounded corners to the frame from hard vignetting.

We are fortunate that we can correct chromatic abberation fringing in our computer tools. I still scan a lot of film and my 17-35 almost always needs some fixing at the wider end. So it was probably always there, we never looked closely enough to see it!

Back to the topic: Based on this thread, I think I am going to try and find a clean non-Xi 28-105 to replace my 35-105RS on my film Maxxums. The 35-105 is a sweet *little* thing, but probably not all that great overall. Another topic for another day.

[braeside]

David, I managed to get hold of a new in box 28-105mm RS on eBay at a reasonable price of £107, so look forward to testing it on the the A900, I sold the 28-85mm to partially fund it. I didn't lose out on the purchase and resale of the 28-85mm. BTW the 28-85mm is an odd lens, it is longest at shortest focal length and vice versa.

[David Kilpatrick]

Based on all the images I have been processing - including many at full aperture or just half a stop down - you will not be disappointed. It is very clean at minumum focus at 105mm, which is where most lenses fall down (min focus, max focal length - including the 18-250mm and the 70-200mm SSM G). I've been shooting today with the 24-105mm Canon (great morning, I got my sunshine and frost) and suddenly hit a close focus limit stop I am not used to - it really can't handle close-up wide angle stuff, the close focus is 70cm (2.3 feet) with a small 'macro' safety zone marked beyond this. It's not as bad as the old 28-135mm Minolta (5ft at 28mm, but with a real macro which could get you down to inches), but not what I expected from a modern lens. I think focusing down to around 30cm, preferably closer, is necessary at 24mm.

David