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Vivitar 19mm f/3.8 on Pixco Focal Reducer
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PostPosted: Fri Oct 13, 2017 6:31 pm    Post subject: Vivitar 19mm f/3.8 on Pixco Focal Reducer Reply with quote

I've had this lens for quite a few years now, originally bought for wide-angle reach on crop cameras.
Its been decent enough but in the end it was no better, and in some ways worse than the kit 18-55 on the wide end.
More convenient as an MF lens, often enough, especially for hyperfocal/scale focus use where it is much faster to bring into action than an AF.

PJCT6740 by luisalegria, on Flickr

I recently happened across a USED Pixco (that is, a no-name) focal reducer in PK-Nex mount for a very low price. These things are $70-80 new; I expect a flood of them in the used market in a couple of years for next to nothing.

Anyway, I had to try the 19mm on it of course. I will do likewise for other wide lenses I expect.

My original posting on the Vivitar 19mm f/3.8 -

http://forum.mflenses.com/vivitar-19-3-8-my-new-favorite-lens-t7961,highlight,%2Bvivitar.html

This is a Cosina made lens rebranded by Vivitar as usual. It was supplied in a couple of different cosmetic layouts, it is all-metal and as usual in the period (1980's) very well made and nicely finished. Its a consumer-grade item and certainly not a contender for professional use. The first mention I have of it is in mail order listings from @1989, mine is apparently from 1991 per the serial number.

The Pixco (Pixco is a distributors brand of Chinese-made photo products) focal reducer is the cheapest of these sorts of devices, all copies to to some degree of the original high quality Metabones Speedbooster of 2013. These things are lens mount adapters (for mirrorless cameras only) with optical elements that compress the lens image circle to give the effect of full-frame rendering on an APS-C or 4/3 sensor.

In this sense the Pixco does exactly as specified - my 19mm coverage exactly matches what my wide-zoom APC-C only Sigma 10-20 manages at the 13mm setting, or what the 19mm FOV is on my Pentax MX viewfinder. The 19mm is once again a very wide lens on my APS-C Nex-7. This is an extremely handy combination, quite compact, fast to use, extreme coverage, great for street photography, etc.

However, there are considerable drawbacks. The worst feature of the Vivitar 19mm was very bad flare. If you like a stream of flare artifacts (hexagons say, 1970's zoom lens style to go along with sideburns and Camel cigarettes) with the sun in the frame or close to it, this combo may work for you. Otherwise the focal reducer doesn't help at all and may make it worse. The 19mm wasn't too bad with distortion; the focal reducer adds considerably to distortion. If you are obsessive about straight lines don't bother. Corners can vary a lot, from acceptable to horrible. Overall if you care about landscape corners shoot at f/8-f/11.

One quirk of the focal reducer (and all focal reducers it seems) - Infinity shift. If you care that your distance scale matches actual focus, the optical block in the reducer needs to be shifted (all of these have some way to do this) to adjust infinity to match. And this changes by lens and focal length. On a zoom lens (like the Tamron 24-40 I am testing with now) if infinity is exact at 24mm, you wont get to infinity at 40mm.

Anyway, samples below. On the whole I had no severe problems with this, it is very easy to use as a "street" lens.

DSC07050 by luisalegria, on Flickr

DSC05681 by luisalegria, on Flickr

DSC05696 by luisalegria, on Flickr

DSC07038 by luisalegria, on Flickr

Note corners above

DSC06973 by luisalegria, on Flickr

The Canadian AF Snowbirds, San Francisco Fleet Week.

DSC05951 by luisalegria, on Flickr

DSC06361 by luisalegria, on Flickr

DSC06301 by luisalegria, on Flickr

DSC06218 by luisalegria, on Flickr

DSC06189 by luisalegria, on Flickr

DSC06157 by luisalegria, on Flickr

DSC06133 by luisalegria, on Flickr

DSC06126 by luisalegria, on Flickr

DSC06116 by luisalegria, on Flickr

DSC06066 by luisalegria, on Flickr

DSC06042 by luisalegria, on Flickr

DSC06025 by luisalegria, on Flickr

DSC05918 by luisalegria, on Flickr

DSC05860 by luisalegria, on Flickr

DSC05985 by luisalegria, on Flickr

Distortion -

DSC05731 by luisalegria, on Flickr

More Distortion -

DSC05752 by luisalegria, on Flickr

Flare -

DSC07018 by luisalegria, on Flickr

More flare, f/8 - Compare with shot below, from Sigma 10-20 (at 13mm)

PJCT6718 by luisalegria, on Flickr


PostPosted: Sat Oct 14, 2017 12:06 am    Post subject: Reply with quote

Some softness on the edges, but geez, Luis, not bad at all! I've been procrastinating buying a focal reducer for my NEX; guess I shouldn't be putting it off any longer.


PostPosted: Sat Oct 14, 2017 3:05 am    Post subject: Reply with quote

Like 1 Like 1 Like 1 Impressive Luis! Had not expected such performance, but well in YOUR hands... Wink

Gosh do I miss SF, wonderful city...