A question about lens 2x extenders

[Ahmed Shahat]

Hello,

I have a Canon 550D camera and looking for a 2x lens extender. I did some search on Amazon. I found many products from Canon and other manufactures with variety in prices and specifications.

Can someone guide me how to choose a suitable one.

Thanks.

[Donald]

Ahmed

I do not recall anyone on here ever writing about having an extender/tele converter, other than those made by the Canon or Nikon.

So, I do not know if there is anyone who could give you comments on the relative merits of various products. There are a number of lens review websites where opinions will be expressed. So far as Canon is concerned, my understanding is that the Canon product, which is of course quite expensive, is the best quality product available. But, as always, it is a question of balancing off the quality against your budget. It is pointless stating that Canon product is what you need if you cannot afford to purchase it.

[inkista]

Ahmed, if you want to retain autofocus, you can only use a 2x teleconverter on an f/2.8 lens. The dRebel bodies will stop autofocusing if the max. aperture of the lens reaches f/8, and a 2x teleconverter adds two stops to the max. aperture of any lens it's used with. So, essentially, if you're purchasing a Canon 2x to use with a Canon lens, you're mostly limited to the f/2.8 L lenses.

You can work around this by taping over the pins, or getting a cheaper 3rd party teleconverter that does not report to the body, but only passes through the lens signals, but chances are good that a cheaper 3rd party tc will also add softness.

Most of us would recommend getting a 1.4x tc instead. It will only add one stop to the max. aperture, and will probably provide better optical quality, making it a better value.

Whatever you do, you will need to be able to get by with manual focusing or to find some kind of way to work around the autofocusing system, if the lens you want to add the converter to has a max. aperture of f/5.6. Using a tc is not the same as having a longer lens.

[rpcrowe]

Even the Canon 1.4x TC can only work on selected Canon lenses. It will not physically fit on others. The Kenko and other TC's will physically fit on most Canon lenses however, there is quite a IQ loss on all but the top-line Canon lenses.

Canon 1.4x TC compatablity chart...
http://www.bhphotovideo.com/FrameWor...xExtender.html

[Colin Southern]

You can work around this by taping over the pins

Some swear by this technique -- but I think more swear at it. AF can get to be more "miss" than "hit".

[Ahmed Shahat]

Thanks all for your time and for that valuable information.

Ahmed

[William W]

What lens(es) do you want to use with a tele extender?
What are all the lenses, that you have?

WW

[Black Pearl]

They are more hassle then they are worth.

Really good ones like Canon and Nikon's own are excellent but they are matched to excellent lenses simply not fitting on lesser glass.

The cheaper ones will fit pretty much anything but the quality is usually grim, added to the fact you're putting them onto cheaper glass (you'd be buying the proper ones if your lenses were better) so you're magnifying the limitations of the original lens. That's before the lack of AF rears its head and makes using the combination a nightmare to use.

I'm sure there are people out there who will swear they are the best thing they ever bought - if it's working for them then I ain't gonna argue - but my advice is don't bother. I have sold countless numbers of the things over the years and I can't recall a single customer coming back saying it was brilliant......"I told you so" doesn't always go down well but I did.

[Ahmed Shahat]

Hello William (Bill),

I'd like to use the extender with Canon EF-S 55-250 mm f/4-5.6 lens. I have another one Canon EF-S 18-55mm f/3.5-5.6 IS II Lens (comes with camera package).

Ahmed

[Black Pearl]

Don't bother.

Seriously you'd be wasting your cash - save up and just buy something longer.

[William W]

I'd like to use the extender with Canon EF-S 55-250 mm f/4-5.6 lens. I have another one Canon EF-S 18-55mm f/3.5-5.6 IS II Lens (comes with camera package).

Thanks for answering.

Absolutely pointless on the 18 to 55 as you already have 55 to 250 and seriously, you would indeed be wasting your cash on the 55 to 250 even getting a x1.4: just save up and just buy something longer.

The 400/5.6L or 100 to 400/4.5~5.6L as examples.

WW

[Ahmed Shahat]

Thanks Bill and Robin for your advice, I'll consider this.

Today I tried to catch the unique phenomenon of Venus crossing the front of the Sun using 55~250 lens. I got acceptable results with respect to lens focal lens . I used gray dark filters to diminish the brightness of the Sun. I will share these photos sometime later. Again, thanks for your time and advice.

Ahmed

[Bill Yeung]

i researched on the 1x and 2x with my 70-200L IS USM f 2.8.....
having know that i need to sacrifice aperture stop, I quitted.
Adding a extender ( get some longer reach) but sacrifice quality just don't work in my case.

and since then, I keep on having dream about the 400, F 2.8.............. LOL

[William W]

Of the three 70 to 200F/2.8L lenses the EF 70 to 200F/2.8 L IS USM is the worst of the three in respect of IQ when attached to the Canon MkII Tele Extenders, however the combination will still produce very good to excellent results.

The second best is the EF70 to 200F/2.8L USM and the best to combine with Canon Tele-Extenders is the EF 70 to 200F/2.8 L IS MkII USM – and that lens with the MKIII Extenders.

The shot above is made with the 70 to 200F/2.8L USM + 2.0MkII and the combination was used at 400mm: An enlargement for better IQ scrutiny appears below the main shot.

Shooting - F/6.3 @ 1/640s @ ISO250.
Transverse Motion - Hand Held: at 1/640s I am reasonably confident - though 1/1000s and faster is much easier.
Note this is the lens stopped down only 1/3 stop.

IMO the x2.0MkII is a pretty handy device to have in the kit: but its use is selective to specific Canon Lenses.

The 400F/2.8L a magnificent lens, but is heavy and for the odd shot in reasonable conditions, the x2.0 (and x1.4) Tele Extenders are useful and are very easy, light weight tools to carry – BUT re-iterating: these Tele-Extenders are useful combined with specific lenses, including the three F/2.8L zooms, which I mentioned.

WW

[jcuknz]

I hesitate to put two alternative approaches to reach becuase of the pre-occupation, quite justified, with the DSLR option. But if you don't have the money you are likely as Donald alluded to be satisfied with less than optimum.
My first approach gives me a 950mm reach with about an f/4.5 aperture, though for best image quality the camera is capable of one is limited to 100 ISO. The outlay for this would be approximately US$500 today and involves getting a Panasonic FZ30 or FZ50 and the Raynox 2025PRO. The camera is discontinued so will be 2/h but the adaptor will be new. [Amazon prices]
I did this first with my FZ30 and organised a lenshood from a plastic drainpipe connector.

The photo also shows the collar with tripod thread, on top so you can see it :) ,so the rig is balanced on the tripod. From memory the Raynox has a 62mm thread at its rear and the camera is 55mm so a step-up ring makes the connection. Unlike current models the FZ30/50 have their lenses in position 24/7 like a DSLR lens.
I gave my FZ30 to my son so the rig uses my FZ50.
You can get similar reach with similar restrictions with regard to ISO with a new camera, the x40 zoom that somebody makes [Canikon?]
The second suggestion which gives you similar ISO potential to the DSLR is of course an M4/3 camera where that 55-250 will have an angle of view of 110-500 instead of the current 88-400. [Really not much improvement] but you can get 100-300 f/5.6 lens which gives you 200-600 AoV.
People have mentioned the need to get that expensive f/2.8 lens to use with the converter as the slower lenses do not focus properly at apertures smaller than f/8.
I played around and organised a rig, which I will not reccomend, where I added an Olympus TCON x1.7 to the 14-140 zoom that my G3 normally carries. It is not a good match and there is slight vignetting which means I have ended up with a 500mm reach at f/10 [ or so ]. Unlike the f/4.5 when used on my FZ50.
HOWEVER .. the point of this is that the contrast detection of the G3 [ at leastr the 014140 lens does it ] works fine and snaps into focus even at f/10 so long as there is a little bit of contrast to work it :)

So often there are swings and roundabouts when considering approaches in photography and it does appear that contrast detection focusing works better than phase detection in this situation. So a M4/3 body with a viewfinder coupled to even a slow, say f/5.6 500mm lens, manually focused of course could be an ecconomical solution for you. I purchased an Olympus E-PL1 recently with the intention of using a legacy 90-230 f/4 Tokina [ that is 180-460mm AoV] but have not got around to using it so it just an idea at present. I am also lazy and prefer to have auto-focus so likely I will be using the G3-014140-TCON rig in preference which has a touch more reach despite the f/10.

This was my test shot when I simply held the TCON in front of the 014140 and it suggested it was worth getting a step-down ring for a fixed mounting.

[jcuknz]

Postscript ...shown is the Raynox 2020 which doesn't have a lenshood thread but the recent 2025 model has, I think an 82mm thread for a hood, which is also available from Amazon. With my very unscientific test the Raynox wasn't as sharp as the TCON ... but with just one shot with each simply holding the adaptor to the lens it was probably me rather than the adaptor.

[William W]

Postscript:

This has been a topic which I have been researching on and off for the past several months.

Not withstanding my previous advice to the OP:



I understand there is NOT any tele-extender presently made, which will allow an EF-S lens, to mount to it.



WW

[DanK]

Ahmed,

I think you are out of luck, for two reasons.

One reason is that your lenses are fairly slow--small maximum aperture (large f-numbers). As one person noted, you will lose autofocus if you use an extender.

The second is this:

I understand there is NOT any tele-extender presently made, which will allow an EF-S lens, to mount to it.

I have never investigated this, but it makes sense. EF-S lenses are built with a back element closer to the sensor. They can't be used on full frame cameras because the smaller clearance is not enough for the mirror. That probably makes it impossible to mount on most or all teleconverters.

Unfortunately, high-quality long lenses, including the Canon lenses that will accept Canon teleconverters, are very expensive.

Dan

[rpcrowe]

I have a 1.4x TC which, combined with either my 70-200mm f/4L IS lens or my 300mm f/4L IS lens provides pretty nice image quality and still maintains very decent auto focus. However, even with top-line lenses like these, if I were to use the 2.0X TC, i would lose out on auto-focus on my 7D cameras.

That is a thorn in my side. I wish, when Canon was deciding on the specifications for the 7D, that they had included auto focus at f/8 in the package.

That is not so much because I would want to use a 2.0X TC on either of the above lenses but, because I would like to use the 1.4x TC on my 400mm f/5.6L lens.

I guess that Canon did not want to take sales away from the 1D line of cameras. However, I doubt that auto focus at f/8 is a great selling point for the 1D cameras...

[William W]

I understand there is NOT any tele-extender presently made, which will allow an EF-S lens, to mount to it.

I have never investigated this, but it makes sense. EF-S lenses are built with a back element closer to the sensor. They can't be used on full frame cameras because the smaller clearance is not enough for the mirror. That probably makes it impossible to mount on most or all teleconverters.

Yes.

It is impossible even to mount any EF-S lens on all (existing) Tele-Extenders even if the glass didn't get I the way - because ALL the existing Tele-extenders have an EF Lens Mount on their Female End.


But since I originally answered the OP last year, I have been scouring various sites that sell photographic “oddments”.

And I can’t find any Tele-extender which has an EF-S mount on its female end.

BUT - I would have thought that some enterprising shop (especially in Asia somewhere) would have tooled one up – whatever the optical quality of it.

To design one is entirely possible.

Considering that there are so many other “lens oddments” which are available, I was surprised I could find one.

WW