Pentax A 28-80 f3.5 - 4.5 lens on Sony a6500

I'm continuing to search for a half decent walk around lens for my Sony a6500, having tried and discarded the Zeiss and Sony offerings. My latest discovery is a Pentax A 28-80 f3.5-4.5 zoom from the film era. I've had my copy for years, bought second hand it's not in the best of condition, with marks visible on the front element and a general slackness in the zoom helicoid. This is what it looks like on the camera.

Be warned, this is a manual focus lens, if that's not your cup of tea, read no further!

It's no lightweight being of mixed metal and plastic construction. With adapter it weighs 502 g, but this is appreciably lighter than the Tamron 28-80 that I have also tested.

How does it perform, I've not conducted any brick wall tripod tests as yet, but having taken a number of shots with it I am reasonably impressed.

Here's an example. It was a muggy, hazy day with poor visibility, but the image quality is OK

First of all the overall view, the German cruise ship Mein Schiff 3 moored at North Shields terminal.

(Click any image for a larger view)

Now actual pixel crops from the extreme left and right of the image

The edges are far better than either the modern Zeiss or Sony zoom achieved, but the overall image lacks a bit of contrast. I really do need to do some formal testing on a bright sunny day.

I need to compare this lens with the Tamron 28-80 that I have also tested, and with some of my old film camera primes.

Sadly, further shooting has revealed a fatal flaw with this lens, at closer distances and probably due to the ravages of age, it does not always achieve sharp focus in the centre of the field. Take a look at this image of some ironstone rocks and the actual pixel crops from centre, left and right.

The overall picture

Centre crop

Left crop

Right crop

The camera was focused on the centre point, so this should not be a field curvature issue. Further I have more examples showing the same pattern. Maybe the wobbly focusing ring is the culprit? This particular copy of the lens is unusable, but I would like to get a hold of another example as, surely, this can't be a generic fault!

I've since carried out a tripod and wall test. Out of 15 images only one displays this fault, taken at 35mm and f8. Two other shots at that focal length and aperture do not.

Edit 28-8-19 - blurred centre!

Comments

Sony 28-70 FF lens on a6500

Since my kit 16-50 lens failed and was pronounced unrepairable I've been looking for a replacement walk around zoom, or, in my case, a lightweight lens that I can carry when cycling. I tried the Zeiss 16-70, but as my previous post here demonstrated, that lens was fatally flawed - as well as being expensive. I was persuaded to try the much cheaper 28-70 lens (cost £234 new) that is supplied as part of the standard kit on Sony full frame cameras. Let's give it its full title, the Sony SEL2870 E Mount - Full Frame 28-70 mm F3.5-5.6 There are things to admire about this lens. It's compact and lightweight and handles well on the a6500. Despite being of plastic construction, it does appear well made, with a metal mount and a robust feel to it. I liked using it. Mounted on a tripod and shooting test pictures against a brick wall the lens is OK, nothing like as sharp at the edges as in the centre, but usable. Here are a few crops from a test shot at 28 mm and f8. The upper...

Commlite Canon EOS to Sony E adapter

I possess two Canon DSLRs and two Sony mirrorless compact system cameras. The big full frame Canon I find too heavy to carry around, and, outdoors, I tend to use the Sony most of the time. However I have a small collection of good Canon lenses that might be useful on the smaller camera. You can buy cheap adapters to fit Canon lenses to Sony cameras, but they do not allow adjustment of the lens aperture, auto focus, or in lens image stabilisation. Alternatively you can spend rather a lot of cash and buy a top of the range adapter, e.g. Metabones, which will give full electronic contact between camera and lens. I don't think that I will be making that much use of my Canon lenses on the Sony, as carrying heavy full frame lenses rather defeats the purpose of using a lightweight compact camera. However I would like to make occasional use of them, possibly in connection with a tripod, and the lens that I would particularly like to fit is my Sigma APO 100-300 f4 . I used t...

The Sigma 100-300 f4 on a Sony a6500

Just to prove that it can be done, here's an example of the Canon EOS fit Sigma 100-300 f4, at 300mm, mounted using a Commlite adapter, on a Sony a6500 APS-C camera. The effective focal length is 450 mm, and the aperture used f10. The assembly was mounted upon a tripod. OK a particularly uninspiring subject, the view from our bedroom window, but that's not the point! The entire image (click for a larger image) An actual pixels crop from the extreme left side of the image. Given the distance involved and the atmospheric conditions I think that's pretty good, certainly usable.

Bryan's New Photo Blog

Search This Blog