Tamron SP 350/5.6 DIY reapair or send it to a Professional?

calvin83 · Joined: 12 Apr 2009 Posts: 7495 Location: Hong Kong

For non-moving objects, I use two second timer on my camera to allow a relatively low shutter speed. This will help to eliminate the vibration of pressing the shutter. You may also set the camera in continuous shooting mode, press down the shutter button and pick the best photo afterward.

marcusBMG · Joined: 07 Dec 2012 Posts: 1298 Location: Conwy N Wales

heres a few test pics on my 06B for comparison pentax K-r, 12 MPx, jpg's

Its not a very good set up, the lighting in particular is too dull, although I was trying to use a couple of reading spots to brighten up a bit. distance ws about 4-5m, depth of field is therefore about 3-4cm. 100% crop:

Here's one from outdoors, about 30m distance, DoF about 1m+:

UPDATE the sun came out so I retook the pics, and (below) tamron Nestor 400mm f6.9 for comparison. Left the previous pic posted because it illustrates the importance of lighting.

06B gives typical mirror shots: inherently dull contrast, and TBH I find that these lenses are tested by high pixel/high pixel density sensors. if you're using a 16MPx, then actually the pics you got may well be as good as you can get. RAW does better with more leeway to oomph the contrast and sharpen.

calvin83 · Joined: 12 Apr 2009 Posts: 7495 Location: Hong Kong

Mirror lenses need sufficient light to give good results. My 06B have good resolution, decent contrast and almost no CA. Here is an 100% crop of a fence roughly 70 meters away without any sharpen.

With a bit of sharpen, the result becomes pretty promising. It will be even better with the contrast and charity boosted.

visualopsins · Expire: 2021-06-22

mo · Expire: 2016-07-30

It has been suggested that I boost my iso setting higher than I normally would. Your 06B images look about the same as mine so perhaps it is performing within the accepted range for this lens?

mo · Expire: 2016-07-30

I got a little bored so thought I would try the G1 with its VF and fine focus,amazing difference I do know this sample is spot on for focus. The VF makes a difference.I also remembered to bump the iso higher.

G1 iso 800 tripod and fine focus https://app.box.com/s/yhu9j1zwgfx00rjic8v6 JPEG,I have not shot with raw on the G1 as yet. this was using the Fotassy adapter M42-M4/3 which I note was a little loose...combined with the Orginal M42 Tamron adapter.

calvin83 · Joined: 12 Apr 2009 Posts: 7495 Location: Hong Kong

Congrats! The photo look good to me. The M4/3 cameras are pretty good on testing the resolution limit of manual lens thanks to their high pixel density.

As visualopsins suggested, I think it is OK to boost ISO to 800 or 1600 under sun light to keep the shutter speed high. The noise will only visible in the dark area.

mo · Expire: 2016-07-30

Do you think I can conclude from these tests, that there is no fault with the lens, and it is within the normal range in the way it produces images?
I wish my K200D was still working so I could test it on a heavy bodied DSLR.

calvin83 · Joined: 12 Apr 2009 Posts: 7495 Location: Hong Kong

I think the resolution and contrast is consistent with the result of my copy. It does not seems there is any fault from the samples you have posted.

marcusBMG · Joined: 07 Dec 2012 Posts: 1298 Location: Conwy N Wales

Final test - my standard shot of the castle tower.

Crops:
1. off the card jpg

2. pp'ed from RAW

These crops comfortably stand comparison with the same subject shot with my other TP's including eg tamron 200-500mm. Under these conditions, and range the mirror is at its best IMO. And also IMO it's more the sensor on my K-r that's the limit rather than the lenses.

I've put a couple more pics in the mirror thread, manual focus lenses.