11 December 2012

Testing add-on tele and wide angle convertor lenses

Keith | Article, Articles and reviews, Hardware review, Lens, photo-hacks | No comment

Add on tele and wide angle convertor lenses

Assorted lenses added to the front of other lenses…

Part of our series of brief lens tests, using various lenses we found laying around the office…

Add on lenses were a popular adjunct for some cameras in the past (cine and still) where the standard lens was fixed (whether zoom or fixed focal length.

Keith has acquired several of these impressive looking bits of glass over the years, and decided to see if they were any good for anything more than seeing what would attach to what.

Using old lenses

Sometimes it’s fun just trying to take some photos with the limitations of a particular lens – sometimes I’m just curious as to how much better modern lenses have become and need reminding why I spend so much on lenses for our business here at Northlight ;-)

Many older lenses can be fitted to your DSLR with a simple adapter. Canon users have a bonus here in that the distance from the mount to the sensor is relatively short, making for easier mechanical design of adapters, such as the Olympus OM mount to Canon EF mount adapter you can see on two of the lenses I’ve used here.

The bits of glass…

The 1.5x and 1.3x adapters at the back and right are called ‘Tele Converters’, and were originally for cine cameras.

The 1.4x TCON-14B and 0.8x WCON-08B were supplied with the Olympus E-20 digital camera. The smaller 0.8 converter came with an Olympus C-1400XL camera.

assorted tele and wide angle conversion lenses

The left most lens shows the most obvious coatings, whilst the older Chinon and Sankyo lenses have fairly minimal coatings by today’s standards (modern lenses really are vastly better in this respect compared to those lenses from the 1980’s you find in junk shops.

Just one other thing you’ll likely need – a set of filter adapter rings

step up adapter rings for filters

Ideally just one ring should cover what you need, since to avoid vignetting, the convertor should be as close to the front of your lens as possible. The rear lens element of the convertor ideally needs to be large enough to cover the field of view.

The 49-62mm step ring worked for the the Olympus convertors with the Zuiko 24mm f/2.8 and 50mm f1.2 lenses I tried.

One warning note here – lenses may not be designed to take much weight on the front, so be careful holding this setup. Indeed, I was going to try this with my Canon EF 50/1.4 lens, but there was so much movement I wasn’t happy going out with it, yet alone forcing the autofocus. Stick with manual focus to start with – I take no responsibility for you damaging the AF on a lens!

Attaching a lens

50mm lens and teleconverter

The back of the Chinon glass has a 58mm thread – I’m going to put adapters on it (mouse over image to see)

Then, the lens is attached (mouse over the image to see)

Adding the lens hood for good measure.

complete lens assembly with lens hood

This gives this, when attached to my Canon 1Ds (The sample photos in the article are taken with my 1Ds mk3, but my old 1Ds is doing some modelling work)

50mm plus converter on canon 1Ds

And oh yes, this most definitely gets noticed when you go out with it :-)

This is ~65mm at f/1.2 at my local pastry and coffee shop…

single cup of coffee

There is minuscule depth of field, noticeable field curvature, massive chromatic aberration, blurring etc., etc.

More so with this view of a pollarded lime tree against the winter sky

winter tree

A man in an orange car.

man in orange car

The lenses

Here’s some more of the set-ups I tried.

A longer tele converter. Note the revised focus scale (this device was for a movie camera)

1.5x teleconverter on 50mm lens

A wide angle converter on the Zuiko 24mm (a good lens – see this look at the 24mm on the 1Ds3)

24mm lens with 0.8x converter

And the newer Olympus ‘Wide extension Lens pro’

24mm lens with newer olympus 0.8x converter

The 1.4x converter on the TS-E90mm – so I’ve got a 126mm tilt/shift lens…

A very large shift lens – TS-E90+Chinon adapter (phone photo!)

There were other combinations, but I’m sure you get the idea…

A few sample images

Here’s a few more images from outside of my home that give a feel for what you’re likely to get with these lenses.

50mm with converter at f/1.2

Using the rather wide f/1.2 setting is always going to be tricky

x1.5 converter in use on 50mm lens

Note the differing magnification between the 1.3x and 1.5x lenses

If you mouse over the image below, you can see (even in this reduced size image) the effect of ‘fixing’ the chromatic aberration in Photoshop ACR (the settings are almost off the scale BTW)

And wider lenses too

Here’s what you get with the WCON-08B attached to the 24mm lens (19mm) – at f/2.8 lots of vignetting and blur.

24mm lens at 19mm with converter

At f/11 everything has sharpened up a lot

using a teleconverter at smaller apertures

Just for comparison, this is the 24mm f/2.8 lens on its own (mouse over image to see change of aperture f/2.8 and f/11)

Longer…

The longer TC worked fine on the TS-E 90mm, but with increased aberrations – enough that if I needed to tilt a lens at this focal length, I’d use a Canon 1.4x teleconverter between the TS-E90 and body.

90mm lens with 1.4x converter attachment

Conclusions

Interesting effects, but hardly items to go in my camera bag on most jobs I work on.

I will admit that the Chinon converter on the Zuiko 50/1.2 makes for some interesting effects – something to file away ‘just in case’.

One side benefit of using lenses on the front of of others is that you don’t get the loss of light through an effective loss of one stop of aperture, of course you get distortion and lots of other effect, but that might not matter.

I’ve never been a fan of using bad cameras just for the sake of it – sure, I can find it fun to go out and take some shots with one of these lens combinations, and just see what turns up.

That’s fine but what am I going to do with such images – probably not a lot – and no, I’m not an instagram fan either.

I didn’t have one at hand, but I’d be interested to see how the converters perform on the standard ‘kit lenses’ you get on some DSLRs.

My suspicion is that with slower lenses, with smaller front elements, the distortions that I’ve highlighted would be much more under control.

big lens - front view

Summary

Interesting experiment for altering the look you get from lenses – if you find one of these teleconverters in a junk shop somewhere, well worth the few quid they can go for.

Here’s the rest of my optical ‘junk’ drawer BTW

assorted optical bits and pieces

Just remember that (IMHO) it’s about actually taking photos not just the techy stuff!