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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 image is a 1024 actual pixels crop from the centre of the frame, while the others are from the bottom left and right corners.

Click any image for a larger picture.



Centre 731 KB


Bottom left 409 KB


Bottom right 531 KB

The bottom right corner looks to be sharper than the bottom left, indicating a decentered lens. I've provided the JPG file sizes, and while they do illustrate the variance in resolution,  they need to be interpreted with some care as the lighting was not uniform.

The situation in the field was not satisfactory. Most shots were OK, not as sharp as I might have got with my old film primes, but acceptable. Some had areas of inexplicable unsharpness however, to the extent that I regarded them as being unusable.

It has been suggested that this might be associated with the optical steady shot OSS stabilisation that is built into the lens, or the In Body Image Stabilisation IBIS that is available in camera. I therefore tried shooting with the stabilisation switched off. This might have brought about some improvement but I still found the odd photo with a blurred patch. I should make it clear at this stage that the IBIS works fine with my old manual focus lenses, provided that I remember to set the appropriate focal length!

Then you might ask the question, do I want a £230 lens that doesn't allow me to make use of IBIS?

So here's a couple of samples to show the problem. This first shot was taken with OSS on. Click for a larger image. The two crops are of actual pixels and  1024 wide. The central section is OK, but that from the left side is noticeably soft. (34mm f8)



Overall view


Centre


Top left

Here's another, this time with the OSS switched off. Again central sharpness is fine but the bottom right quadrant is pretty poor.







I decided against keeping the lens. Bought from Amazon I was able to return it free of charge and obtained a full refund. Irritatingly I managed to lose the lens cap and therefore had to fork out for a genuine overpriced Sony replacement before sending it back! 

Maybe I got a bad copy, who knows?



Comments

  1. Hi Bryan,
    I followed your original post on Alamy. Sorry your trials and tribulations continue. Are you tempted to get another 16-50 ? Mine has proved fairly sharp and reliable, just the odd failing to retract.

    Dave Humphreys

    ReplyDelete
    Replies
    1. Hi Dave

      Probably not, a friend bought one used and it failed almost immediately, fortunately he got a full refund. I have a couple of old Pentax zooms that I might experiment with.

      My 16-50 was Okish, better at the edges than either of these two more expensive alternatives, but the images lacked sparkle overall. Having said that it was certainly good enough to pass Alamy's QC and I sold a few photos taken with it.

      Delete
  2. Now funny you should mention Pentax. I've been brand loyal to them since film days. About a year ago a good deal came up on a K70 body. I'd had it about a week when my trusty 18-55 lens packed up. Thought I'd try the Pentax retractable kit lens - fiddly to use and poor IQ so it went back. I asked the dealer for a recommendation, try and get an 18-55 Mark II he said. Found one on EBay but not impressed with the sharpness. Finally settled on a new Tamron 17-50 which is a fine lens but it's so heavy; as a result I've been using my A6000, which was supposed to be a back up, almost exclusively. Hey ho !

    ReplyDelete
  3. Yes I used Pentax for years, the viewfinders on the ME and MX are better than anything I've seen on a DSLR. It's only the advent of decent EVFs that has meant the digital has caught up!

    I would like one of those Tamron 17-50 or equivalent Sigma lenses for the a6500, but they don't appear to make one to fit.

    My Pentax zooms date from a prior era. The 75-150 f4 is superb, and the 35-70 not bad. I also have a 28-80 which might not be so hot, but I'll give it a go.

    ReplyDelete

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