M4/3 System - Lens Evaluation

Seriously Long - Raynox 2020 Pro 2.2x Teleconverter.
(5th Feb 2017)

Purpose: To test if it is possible to further extend the telephoto reach of some of the longer Panasonic and Olympus M43 telephoto lenses - and particularly the Panasonic/Leica 100-400 lens, - for use in a practical working environment, and with useable results?

Raynox 2020 Pro attached to the Panasonic/Leica 100-400 and GX7.
Spec: 2-group/4-element, High Definition Coated optical glass elements.
Front Filter thread: 82mm. Mounting thread: 62mm.
Dimensions: 123mm x 86mm. Weight: 275g.

Lens Evaluation: Raynox 2020 Pro (2.2x afocal teleconverter)
                              which multiplies the normal zoom length of a lens by a factor of 2.2.

  Lenses Used:
           Olympus 40-150 f 2.8pro (inc. + 1.4x matching converter).
           Olympus 75-300 Mk2.
           Panasonic 100-400.

  Cameras Used:
           Panasonic GX7. (16Mp with in-camera stabilisation).
           Panasonic GX8. (20Mp with in-camera stabilisation).

Step Ring Connection
A 72mm to 62mm Step-Down Ring is needed to connect the 100-400 to the Raynox 2020.
What a Shady Job!
I am pleased to say that Raynox can now supply a proper shade for the 2020 lens which
looks a lot nicer than the home made one (shown above) that I 'crafted' over 10 years ago!

This is not a scientific lens test, all images displayed were taken during 'practical use' photography and thus will allow me to evaluate whether there is any benefit of using the Raynox 2.2x afocal teleconverter to multiply the available maximum optical zoom, when it is attached to the front of any of my current lenses. Of specific interest for maximum achievable reach for an autofocus M43 system, being when fitted to the Panasonic 100-400 lens. Which in theory if it works will provide a total 'Full Frame Equivalent' focal length of 1,760mm!

Afocal teleconverters attach to the FRONT of camera lenses, as opposed to the type more commonly used on interchangeable lens cameras which fit between the lens and the camera.

Let's get one thing clear from the start, I do not use a setup like this for Landscape photography.  I use it for photographing small objects which are very far away, such as small distant birds which are too nervous to approach.  So edge to edge performance is not the primary consideration, but sharpness and fast focusing is!

Raynox 2020 + Olympus 40-150 Pro & also + the dedicated Olympus 1.4x TC:

The following three Olympus 40-150 Pro examples were taken using a Panasonic GX8 camera with various lens combinations and settings as specified on the images.

When clicking for larger examples: Please note that due to hosting space limitations, in most cases I have decided to present full size crops of the most relevant parts of each image. Where applicable whole images are also presented for viewing, but mainly at the UK national digital competition display size of 1400pixels wide.

Raynox 2020 Pro + Olympus 40-150 Pro. FFE 660mm (Click photo for full size crop)
Even with the converter attached the Nuthatch is still small in the frame, but you will see from the
full size crop image that there is still an abundance of detail available from this combination.      
Raynox 2020 Pro + Olympus 40-150 Pro + 1.4x TC. FFE 924mm (Click photo for full size crop)
I really did not expect this to work at all, as not only am I effectively stacking two different types of teleconverters, I also took the photo with the lens wide open at F4 (which is the maximum available when the rear mounted TC is fitted). Frankly I was impressed at how usable the image still was, mind you the Depth of Field was a bit small at F4, hence the eye was not quite as sharp as I would like.
Note: Rear mounted TC's always cut down a lot of light.
Front mounted TC's cut down very little light.
This squirrel was a bit to close to test even with just the 2020 attached.  FFE 660mm.
(Click photo for larger Image)

If you click on the above image to view a larger version you can see the amount of vignetting present (darkening of the corners) when using the Raynox 2020 on the Olympus 40-150 pro.
This Olympus lens is not stabilised, but the GX8 in body stabilisation worked well.
To view a Full Size Squirrel Crop and see the amazing Eye Detail sharpness - Click HERE.

Conclusion: The Raynox 2020 pro when fitted to the stunning Olympus 40-150 pro, will produce very sharp pictures for the in-focus areas across most of the image frame. It must be remembered however that when the telephoto reach is increased, a much smaller range is in focus unless the lens is stopped down.

There is always a tendency for the Raynox 2020 to produce Chromatic Aberration (CA) and also some Purple Fringing (PF), especially on highlights or out of focus high contrast areas in front of, or behind the subject. However this tends to be far less of an issue when fitted to this Olympus 40-150 pro than some other lenses.  Even so, great care needs to be taken regarding subject and background when using this or any other 2020 combination. And for best results on certain types of images some post processing is essential. More on this later.....

Raynox 2020 + Olympus 75-300 Mk2:

The following two examples were taken using a Panasonic GX7 camera fitted with the Raynox 2020 attached to the Olympus 75-300 Mk2 lens, which was then used at various focal length combinations as specified on the images. 

The Olympus 75-300 Mk2 @ f8 + Raynox 2020 surprised me with some beautiful images.
FFE 1,030mm
(Click photo for larger Image)
This setup focuses quickly and was very stable to handhold (braced) even at 1,030mm focal length, which says an awful lot about the quality of the GX7's in camera stabilisation system.  
I just loved the rear bokeh and the foreground water effects produced by this combination.
       Full zoom on the 75-300 @ f8 + the Raynox 2020 was required to capture this Bullfinch:
FFE 1,320mm.
(Click photo for larger Image)
In camera stabilisation was once again plenty good enough for this leaning over a fence grab shot.
To view a Full Size Crop for feather detail - Click HERE.

Conclusion: I have always thought that the Olympus 75-300 Mk2 was a terrific bargain, whose price belies its optical quality. Even so I did not expect it to be good enough to work with the Raynox 2020 attached, but how wrong I was. This combination provided terrific reach and accurate focus, thus enabling me to capture small birds in far away branches with very acceptable results. The combination isn't perfect, but used correctly in the right circumstances it is able to produce more than acceptable images.

Introducing Chromatic Aberration:

The following set of images were from one quick snap of our old satellite dish, taken the very first time I fitted the Raynox 2020 to an M43 lens (my Olympus 75-300 Mk2) to see if it would work at all. And the result provides a good introduction to Chromatic Aberration (CA) in the system. I can not remember if at that time the Panasonic cameras were programmed to remove CA from Olympus lenses using firmware, but in my experience the Olympus lenses always seem to perform very well in this respect even without any extra software processing.

Unprocessed Chromatic Aberration Example: Olympus 75-300 Mk2 + Raynox 2020 Pro.
FFE 972mm.
(Click photo for larger Image)
Lets examine areas A and B from this unprocessed  Out Of Camera jpg, shot taken at the full-frame equiv. of 972mm. As will be seen clearly from the full size crops below, the central part of the image Area-B has only a tinge of CA, but the the out of focus Area-A has a pronounced red-cyan glow.
Above: OOC Area-B unprocessed shows a slight colour tinge around the holes
(Click photo for larger Image)
Above: Unprocessed, this OOC Area-A which is near the edge of the picture frame, shows pronounced red-cyan chromatic aberration around a slightly out of focus arm.
(Click photo for larger Image
Photo after processing to reduce chromatic Aberration.
(Click photo for larger Image
          Examine closely the full size crops from Area-B and Area-A below to see the improvement.
Above: OOC Area-B after image was processed to remove chromatic aberration.
(Click photo for larger Image)
Above: This slightly out of focus arm has also had most of its CA corrected during the processing to an acceptable level, but it can not be corrected entirely, due to it
being slightly out of the focal plane.
(Click photo for larger Image)
Even using F8, at this incredibly long focal length only a small part of the image was in focus.         

Once again Chromatic Aberration can be a problem and ideally needs to be processed out as shown above, but it is a price worth paying if it allows the user to get images that would otherwise be out of reach. One other small point of note to bare in mind is that this 2.2x Afocal teleconverter will also double your minimum focusing distance, which on the 75-300 was a bit of a nuisance at times when the birds came close!

The Olympus 75-300 Mk2 lens quality at full zoom is absolutely fine with the converter at F7.1. But with this long reach the depth of focus is very small unless the lens is stopped down, which is why I shot these photos at F8.

Raynox 2020 + Panasonic 100-400:

Well this was the big test, because as far as I am aware there is currently no other way to achieve this amount of long zoom reach from an M43 lens setup that will still autofocus fast and even in poor light.

With the potential of a full frame equivalent focal range of 1,760mm on tap, this was just far too tempting not to at least try. But would it be any good?

GX7 + Panasonic 100-400. FFE 800mm. (Click photo for larger image) 
With the Panasonic 100-400 at full zoom the Bearded Tit was very small in the frame. 
Although slightly underexposed the image from this lens has good contrast, colour and clarity.
GX7 + Raynox 2020 Pro + Panasonic 100-400. FFE 1,540mm. (Click photo for larger image)
Even though not at full zoom, with the Raynox 2020 attached the Bearded Tit although
now further away, was much bigger in the frame. 
But... This combination produces very washed out images, with little contrast
and for some reason causes the camera to over expose!
Plus colour fringing is also noticeable and discolours the image.
 However all is not lost, as there are things we can do to improve the situation: Dialling in negative exposure compensation can help and in two ways. First it allows a faster shutter speed - always helpful when photographing birds, - and it also helps improve the colour and contrast a little.

So is there any useful gain at all to be had with this 2020 + 100-400 combination?

The Panasonic 100-400 and Raynox 2020 Pro is not a terrific combination for general usage, and it can be very difficult to process the resulting image to achieve a useful gain. But as it is currently the only game it town if you need a huge amount of magnification that will autofocus, let us look more closely to see the pros and cons and if we can gain a worthwhile improvement over using just the 100-400 by itself...

Note: All photos on this review page are handheld, even those at FF equivalent of 1,760mm !!!

GX7 + Panasonic 100-400. FFE 800mm. (Click photo for full size crop)
The images directly above and below are identically sized crops taken from the previous Bearded-Tit photos and are to illustrate in a practical manner the differences in picture quality and what can be achieved with a little work to improve the teleconverted photo.
Before Processing: GX7 + Raynox 2020 Pro + Panasonic 100-400. FFE 1,540mm.
(Click photo for full size crop)

Although there is certainly far more fine detail to be seen in this teleconverted photo, the low
contrast and discolouration is quite a severe problem to deal with and needs processing.
After Processing: GX7 + Raynox 2020 Pro + Panasonic 100-400. FFE 1,540mm.
(Click photo for full size crop)
After a small amount of processing has been quickly applied to remove the purple coloured fringing and also to increase local contrast, the image is already greatly improved. And it can be seen quite clearly that this much feather detail was never going to be obtained by up-scaling image 'A'.

A practical test !!!

Birds in poor light in a very strong wind is definitely not the best conditions for scientific testing of lenses, especially as they don't sit still either. However these weather conditions are typical in the UK and birding is a typical usage for this type of setup. So as this gull did at least stay on the log being blown around for long enough for me to fit the Raynox 2020 teleconverter and try lots of focal lengths, below I present the results...

GX7 + Raynox 2020 Pro + Panasonic 100-400 = FFE 800mm (Click photo for larger 1400px photo)
It was a dull overcast very windy day and the feathers were blowing in the wind, so the higher shutter speed images may well fair slightly better. This was with the camera set at: F6.3, 1/1000, 0 EV. 
AND to view the Full Size FFE 800mm Whole Image - Click HERE.
GX7 + Raynox 2020 Pro + Panasonic 100-400 = FFE 1,100mm (Click photo for larger 1400px photo)
The Raynox was fitted and the 100-400 lens was set at 250 which provided a Full Frame Equivalent total of 1,100mm. This was with the camera set at: F7.1, 1/500, 0 EV.  
This image was processed in Lightroom6 (LR6) to try and reduce CA and see if more detail could be extracted, however I have noticed that with bird certain bird feathers it is harder to extract more detail - without introducing noise - than Panasonics jpg engine already does, which is a huge credit to Panasonic. Note how much brighter the photo is compared to the previous 100-400 (FFE 800mm) image despite the same exposure compensation being set, which I have found typical when using the Raynox in combination with most lenses. So I could have dialled in -1/3 EV compensation which would have also been of benefit regarding shutter speed.
AND to view the Full Size FFE 1,100mm Whole Image - Click HERE.

Example A and B above does show quite clearly that even with small zoom increases, more fine feather detail can be extracted than when the Panasonic 100-400 is used by itself, but detail isn't everything and colour casts and CA are already starting to appear. These aberrations are fairly easily to control at this level of zoom during image processing. I normally use LR6 for Purple Fringing and PT lens for CA, but many programs are available with features for image correction.

The following examples - some of which are OOC (out of the camera) and others are (LR6) processed, - show how things progress when the zoom level on the 100-400 is increased with the Raynox 2020 pro attached.
Please be aware that the gull did move between shots and its feathers were blowing around, so a true scientific comparison is out of the question. But at least you will be able to make some judgements when examining the full size crops. Take note of the purple fringing worsening with zoom level around the beak and also colour tinge in the head feathers on the OOC jpg images. Also on the water behind the gull in the OOC images you may notice that there are greenish streaks appearing with increased zoom level and in certain circumstance this type of CA (Lo-CA) can be much harder to process out.

GX7 + Raynox 2020 Pro + Panasonic 100-400 @ FFE 800mm. (Click photo for full size crop)
Due to the very fine white feathers and the lighting, there is very little detail to be seen on the white feathers, but image sharpness can be judged from the beak and also feathers under the chin. 
GX7 + Raynox 2020 Pro + Panasonic 100-400 @ FFE 1,100. (Click photo for full size crop)
The contrast reduction compared to using the 100-400 on its own can clearly be seen, and although the feathers under the chin look less clear, the white feathers towards the bottom of the picture look far more detailed. Possibly the head may have been slightly out of focus?   
GX7 + Raynox 2020 Pro + Panasonic 100-400 @ FFE 1,320mm. (Click photo for full size crop)
Although unprocessed as can be seen by the slight magenta colour cast and the purple fringing on the beak, the feather detail under the chin is superb and exceeds that from image A.. 
GX7 + Raynox 2020 Pro + Panasonic 100-400 @ FFE 1,400mm. (Click photo for full size crop)
Please not that my LR6 processing may be responsible for losing some feather detail. 
GX7 + Raynox 2020 Pro + Panasonic 100-400 @ FFE 1,540mm. (Click photo for full size crop)
This OOC jpg now clearly shows strange purple patches on the gulls head at this magnification
and also a tinged green streak on the water behind.
GX7 + Raynox 2020 Pro + Panasonic 100-400 @ FFE 1,760mm. (Click photo for full size crop)
At this ridiculously long focal range it is very difficult to handhold steadily enough to obtain a good shot. Also any movement on the part of the gull or wind blowing the feathers will also be greatly magnified, so it is difficult to ascertain why there is not more detail, but the beak certainly looks quite sharp and there are clearly more feathers showing just behind the eye than in image A (100-400 without Raynox).

Dare I say that it is possible that I processed it out? I confess that I have noticed before that using LR6 and trying to remove some noise (these were all shot at ISO800), I have frequently ended up with less feather detail than the original Panasonic out of camera jpg !

Analysis of the Gulls:

Wind blowing the feathers and the gulls head and body moving position from shot to shot unfortunately changed the shadows which enhanced feather detail, thus accurate analysis is difficult. But I think it is fair to say that despite the reduced contrast in the teleconverted images, improvements are there to be gained quite easily and with very little work especially when shooting with less than maximum zoom. At these ultra-long zoom lengths many factors affect image quality, not the least camera movement. These were taken handheld sitting down using a Panasonic GX7 which does not support the Dual IS feature of the 100-400 lens. However in my opinion the camera did an excellent job.

Lo-CA or Longitudinal Chromatic Aberration rears its ugly head...

This 2020 + 100-400 combo suffers two very horrid faults, one of which is difficult to deal with - Purple Fringing, -  and the other - Lo-CA - which is virtually impossible to do anything about. And no this type of CA can not be programmed out or corrected in software, Panasonic or anyone else!

Lo-CA arises when the light rays from objects in front of and behind the focal plane are not corrected optically, which unfortunately means that objects behind tend to have a coloured glow around them and objects in front have an opposite coloured glow around them. ...The actual Lo-CA colours that appear front and back varies with different lenses depending on which colours the lens designers have optically corrected for. See below for an absolutely horrid example...

GX7 + Raynox 2020 Pro + Panasonic 100-400 @ FFE 1,540.   ...Extreme Lo-CA !
This full size camera jpg crop is possibly the worst case scenario of Lo-CA and to my mind creates a totally unusable and unrecoverable image. This image was taken intentionally to show how bad colour aberration can get when using the 100-400 + Raynox combination. The camera was focused on the dark middle branches of a tree against a bright sky. All the out of focus branches behind exhibit green and the out of focus branches in front exhibit magenta. Surprisingly however this does not mean that the Panasonic 100-400 + Raynox 2020 lens combination is never useable for bird in a tree type photography, as there are occasions where it is very useful, please observe the example below...
GX7 + Raynox 2020 Pro + Panasonic 100-400 @ FFE 1,400 (Click photo for larger image)
Please make allowances when judging this photo as M43 cameras are not stellar at ISO1600 when it comes to retaining bird feather detail. This waxwing was on the central reservation of a very busy dual carriageway and it was not possible to get close to it. I could have just used the 100-400 on its own, but the image would have been 1/2 the size and possibly not shown as much detail, as this image was a heavy crop from the centre anyway..
Although present, notice how little the Lo-CA interferes with the subject in this example.
I only processed it in LR6 to increase the contrast and to reduce the slight purple fringing which showed mainly around the waxwings beak and tail feather areas. 
I was shooting alongside photographers with extremely expensive kit:
The chap on my left had a 30mp Canon with a prime 500mm lens and 2x rear mounted TC, which was exceedingly slow to focus. The chap on my right had a Canon 1Dx with an enormous 800mm F4 prime - which did focus fast !!! These were all tripod mounted and their kit was very big and very heavy. I had a featherweight monopod, my GX7 plus the Panasonic 100-400 and the Raynox 2020. The chap on the left didn't get the shot due to focus issues, the chap on the right got a superb sharp shots, but they were fairly small in the frame. I would have loved the clarity of his 15,000 kit but was very pleased with all the photos I managed to grab of the waxwing, one of which I present above


A)  WARNING: As afocal teleconverters are front mounted and can be heavy, they can place additional stress on the primary lens and camera/lens mount if not handled correctly. As such great care should be taken when in use.
Despite its size the Raynox 2020 is very light and handles well. I always hold it and the camera body when in use, which also provides best stability. I would never let it dangle unsupported when fully extended!

B)  A front mounted teleconverter will increase your minimum focusing distance. In this instance the Raynox 2020 Pro will more than double it. IE. If the previous minimum focus distance = 2metres, then it will now be 2metres multiplied by 2.2 = 4.4metres minimum focus distance.

C)  Afocal converters (wide angle and teleconvertrers) usually work far better on small chip cameras than on APS-C or FF. I was very happy ten years ago using this Raynox 2020 Pro on a 28-200mm Minolta A2 bridge camera and would be very interested to see the results of using it on a modern 1,200mm zoom Bridge camera!

D) When using long lens combinations I would heartily advise using a monopod, they are inexpensive, weigh very little and can aid stability when shooting distant subjects considerable. I have attached a strap to mine (using a couple of zip-ties) so that I can sling it over my shoulder for convenient carrying. And there has been a noticeable improvement in the sharpness of photos I have taken - especially when stood up, - since I have been using it.


A massive advantage of front mounted afocal teleconverters is that instead of slowing or stopping your cameras autofocus (like rear mounted ones do), it actually appears to speed it up and provide more accuracy!

Unlike rear mounted converters, afocal teleconverters do not magnify any existing lens errors. I fact it is the lens that will magnify any teleconverter error.

Much more fine detail can be captured when the subject is optically magnified, which is detail that no digital magnification can 'magic up'.


Afocal teleconverters are much  bigger and bulkier than rear mounted teleconverters.

Lo-CA and Purple Fringing are the two worst features that can rear its ugly head and if not possible to deal with, can ruin what may otherwise be a very good image.

It may be tricky finding an optically good afocal teleconverter that works well with your lens... 

Many so called 'Pro' or 'HD' afocal teleconverters advertised on Ebay at low prices, really are just paperweights in disguise. Sadly I know because I have purchased quite a few and should have learned quicker to have bought a good one in the first place. I now have quite a box full and which I would not dream of trying to sell to anyone. Having said that, I have a few wide angle afocal converters from Minolta, Olympus and Nikon, which do work very well. But beware of the ever tempting Fisheye's, many only work well when fitted on certain lenses and usually only very small sensor cameras!

CONCLUSION - So is it worth buying a Raynox 2020 Pro?

Well I was lucky in that I already owned - and have used - the Raynox lens on test for over 10 years. It has been fitted to many bridge style cameras and with great success for birding, dragonflies and butterflies. So it was in my kit drawer already and I am not sure how much they currently cost.

But assuming that you already have one of the lenses on test and need far more magnification without too much expenditure and you posses some processing skills, it may well be worth considering. It is so light I am always happy to carry it in my kit bag. And when fitted to the the two Olympus lenses on test I now know how to achieve very beneficial results.

If you already own the Olympus 40-150 F2.8 pro and need to go longer, I would first advise get the Olympus 75-300 Mk2, because it has double the focal length, is relatively inexpensive, very sharp and has almost no vices, barring slightly slow to focus (in comparison with Pro lenses) and slightly less contrast (also in comparison to Pro lenses).

If you already own an Olympus 75-300 Mk2 and want a large focal length increase, but do not have the big budget necessary for a Panasonic 100-400 lens, then the Raynox 2020 can provide an alternative as long as you can live with its limitations: Reasonably good light may be needed as the optimum aperture I have found with the Raynox attached is F7.1 and F8. The focus is fast and very accurate, but the resulting image does lack contrast which is  easily correctable, but many may suffer from PF and CA - especially at full zoom - which will need processing to good effect. 

From my experience I would be far more reluctant to recommend the Raynox 2020's use on the Panasonic 100-400 unless you either have good processing skills, or are prepared to spend a lot of time learning how to get the best out of it. Even then it will only be really suitable on certain types of images and in certain situations. Getting closer with the 100-400 on its own will always be the best option by far.

However in M43, if you want a the longest zoom reach currently on offer, that is practical to use in the field and are prepared to do some post processing work on the images to get an acceptable result. Then using the Raynox 2020 Pro is currently the best setup I have found for increasing my telephoto lenses focal length. If anyone has a better system that will autofocus fast, I will be very envious and also pleased to hear about it.


  Article Adrian Harris