Teleconverter stacking?.

[Journeyman]

Good day,

Is it possible to link two teleconverters via an extender?

I have a Canon x1.4 and a Tamron x1.4 with the appropriate lenses for each. The converters don’t offer the possibility of joining them.
My mind is suggesting that it may be possible to hook up an assembly of
400 lens - x1.4 - extender- x1.4 - Canon EOS 90D. It would be manual focus only of course but would offer a possible 1250mm focal length including the crop factor of 1.6.

Thank you, kind regards,
Dennis

[ameerat42]

Good evening, Journeyman.
Would you be able to provide an image of the setup? My first thought was that the
converters should just stack behind the lens, and the result attachable to the camera.

Then there is the "extender" - a term sometimes used in the form "tele-extender" in
place of "teleconverter". All I can imagine is that it's an extension tube, such as used
for moving a lens out from a camera body to allow close-up photography.

To speculate further: do you mean that you would have an arrangement such as:

Lens + teleconverter 1 + "extender" + teleconverter 2 + camera

If so, then I could not say what the optical result would be, except to suggest that the
extender would introduce some noticeable vignetting AND that the resulting focal length
would not be a simple doubling of that of your lens alone. In fact, you'd effectively get a:

Lens with teleconverter + and extension tube to render it a "close-up lens" + a teleconverter
multiplying the image. BUT you would not achieve infinity focus.

As I said, post a pic for fine-tuning.

- - - Updated - - -

Some moments after hitting the "post" button I recalled a memory from my filmic past
where I did indeed carry out such an experiment. I had:

50mm lens + 2X converter + extension tube.

It gave me a 100mm lens + extension tube.

In another version I swapped the converter and extension tube, and if I recall
correctly, that was better for "macro" work. Of course, neither arrangement
allowed for infinity focus.

[paulheath]

The design of Canon's extenders ( including 3rd party for Canon ) means that you can't directly couple two extenders together because the protruding glass element physically doesn't fit. The way to get around this is to use a 12mm extension tube between the two extenders:nod::nod:
i shall add, you could couple a 2x with a 1.4x , but not a 1.4 x with a 1.4x , or a 2x with a 2x if that makes sense

[ameerat42]

Ta, that's interesting.

I found this: https://www.canon.com.au/lens-extenders

It looks like you could have a ghost of a chance with the EF versions...
Perhaps make that a wraith of a chance - even slimmer.

So, Paul, can you focus at infinity using the 12mm extension tube like that?

[Journeyman]

Good day & thanks,
The intruding lens mounts definitely cause the problem. I have read articles elsewhere that photographers have used a lightproof non-camera barrel to extend their lenses for macro work.

Nardes used a multi teleconverter setup with great result using extenders however he used all Canon gear, my plan is a hybrid set up.

It is the hollow of the extender and the ability of the mounts to couple that interest me.
The photo shows the fittings and couplers. The better mousetrap (in this case lunar pic) seems to be in reach.

As always, many thanks for your advice, kind regards,
Journeyman



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[nardes]

This worked for me and retained infinity focus.:)

The camera body is the EOS R6.

Cheers

Dennis

146734

146732

[ameerat42]

Revising...

- - - Updated - - -

Does that extension tube read 12mm? Did it induce any vignetting in that position?
(I guess not, though.) How did you get by with the protrusion of the teleconverters?

- - - Updated - - -

---Oh, I see, and will answer my own question: They are EF versions, with hardly
any protrusion :nod:

[paulheath]

jeeeeeez nardes, if thats on a 600 prime your at 5376mm if applied the 1.6 crop mode

[nardes]

jeeeeeez nardes, if thats on a 600 prime your at 5376mm if applied the 1.6 crop mode

I wish I had the 600mm Prime, :D this was on the 100-400mm Mk II.:)

Cheers

Dennis

[ameerat42]

Hi Nardes, I might as well ask you: have you noticed any drawbacks at all, like vignetting,
with the interposed extension?

[nardes]

Hi Nardes, I might as well ask you: have you noticed any drawbacks at all, like vignetting,
with the interposed extension?

I've only used this combo mounted on a tripod when shooting the Moon and then Jupiter and Saturn so I did not check for vignetting.

Also, from memory, I did try something similar on a 300mm F2.8 lens and I think it would not reach infinity focus with the 12mm Ext Tube, so one would need to experiment on a lens by lens basis.

Incidentally, the Canon RF Extenders will not fit into the Canon Model of the RF to EF Lens Mount - you cannot fit the round barrel into the rectangular hole. This means you cannot go EOS R -> RF Extender -> Canon RF to EF Adapter -> EF Lens.

You may be able to do this with a non-Canon RF to EF Adapter if the hole is large enough?

Cheers

Dennis

[ameerat42]

Ta for the info, Dennis.

[Journeyman]

My lens mounts are both circular, EF 400 and EF mount Tamron. It would require a minimum of 16mm to space out the 1.4x mounts.

From a lunar photography perspective one option is a 600 variable lens from Tamron when coupled with a 1.4x, may work although not an inexpensive option. The other is a refracting telescope with a dslr mount.

I have seen astonishing pictures of the moon from good telescopes with stacking of many images, in the 100s. Of course using tracking equipment and specialised cameras. Dennis’s photos show what is possible using DSLR camera and lens combinations with thought and ingenuity.

Remaining budget conscious an extender is inexpensive.

As always many thanks.

[ameerat42]

A slight digression - and a W:eek:KE-UP call!

I've just checked on prices for various teleconverters - brands, mounts, powers...
They range from $519 to $600 - GAH!!!

A few years ago, mine cost $250 (a 2X) :confused013

Rip-OFF van Winkle :(

[Journeyman]

My Canon II was 2nd hand, Gumtree $250 works well, the Tamron as per your quote.

[Journeyman]

Another slight diversion. There are inexpensive tubes available for purchase. Genuine Canon tubes are not cheap, where as the non genuine start as low as $20.00.
Any info would be welcome. Regards JM

[ameerat42]

It's just another gouge-point :rolleyes::rolleyes:

I think we'd better start saving up hens' teeth.

[Journeyman]

Good day,
I emailed Canon to ask whether two [Canon] teleconverters could be coupled successfully. The reply was prompt, good service indeed.

The upshot was that it could done. Manual focus would be required.

A better way perhaps is that a 2X alone would help, focal length of 800 rather than 560 with the 1.4X.

I am after better quality lunar photos, the other possibility is using an equatorial tracking device. Making stacking a more complete option. A basic one is about the same price as a converter. More of the hens teeth savings required. It would be more useful for astro photography though.

Thanks for your interest,
Journeyman

[ameerat42]

Well, 800mm will give you ~8mm lunar image. If you are talking about tracking (equatorial mount)
and then stacking, perhaps an astro tracker would do. You can get to track at star/solar/lunar
rates. Of course it's BYO (sturdy) Tripod. Featured ones are about the same price as a TC or an
eq mount. Have a look at this page for some Oz prices:

https://www.bhphotovideo.com/c/buy/star-tracker-camera-mounts/ci/48647

In the meantime, you could try to improve your PP skills on single image captures. That will
always be necessary, no matter how you capture your image(s).

[Journeyman]

Thanks for the tracker info.

Manual focus technique is something I need to polish up.
PP does offer quite a few opportunities. I don’t always understand what is required particularly related to contrast and brightness. The PP programs need more time from me.

The last full moon shot has developed a green perimeter and latitude lines with saturation increases. No added colours. I will post a photo later this morning.

I will invest more time to follow the PP track. I am reluctant to buy the 2X without good reason. The tracker has a lot of appeal though.

Thanks again.

[ameerat42]

I must say I replied thinking you already had the 2X, but now I see it's a 1.4X.
OK, that's about 5-5.6mm image. Still worth a try, though, especially with some
stacked shots. I routinely use 500mm for the moon and sun, and I too might look
to the idea of stacking. I tried it recently - but for extra depth - on flowers.

[Journeyman]

Good day,
These photos are from a recent series.

1. A JPG converted from a CR3 file, cropped to post on the forum. Otherwise no editing.

2. A TIF taken and converted from a stack of 8 using Registax.
Run through Topaz Sharpen, then saturated using Photoshop.
The blue perimeter and lines of latitude have me stumped. Overall it is not a bad photo otherwise. The craters are reasonably clear.

This is what prompted my search for a higher quality shots of the moon. Nardes shots are the gold standard in my search. To reach someway near that would work well. Operating within a framework of equipment that allows for some changes by swapping gear.

There seems 3 options for astro shots:
Camera and suitable lens structure (+1.4X, 2X etc.?),
Camera, lens etc. and tracking unit,
A telescope and attached camera + a tracking unit if possible.
With respect to Don Quixote perhaps it is an impossible dream and I get on with what I have.

Any hints and help with editing will be much appreciated. Thanks for the time photographers have given. I would like to think that in the future I am able to reciprocate to the forum.

Kind regards,
Journeyman


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[ameerat42]

To me it's the process you're doing with these.

Allow me to be frank, and say that I think your goal of achieving Nardes-like images is
causing you to stumble on the basics, the important one of these being your stated
inexperience with PP. However, from memory, you did produce a couple of fairly good
moon shots in earlier posts.

I would suggest that you do some more practice* on single shots with the max FL that
you can get - with the 400mm and 1.4X, a quite ample setup for the task - and then do
some practice in getting the focus, tones, and sharpness right. After that, try the stacking
and also the saturation.

CC for the shots above:
A good bit of tonal work could be done in the raw conversion stage, rather than just going
to jpeg. Also at the raw stage do some sharpening.

For the stack and saturation exercise, [there appear to be] too many sharpening artifacts
(as bright spots) as well as coloration artifacts, the main one being the blue limb. I think
your meridians are actual features on the surface, such as the ejecta rays emanating from
Tycho crater and that trail across the Sea of Serenity.

Anyway, a longer post to tease out some thoughts :o

* Noun spelling used, in spite of Google's inane insistence that the verb should also be thus
spelt :rolleyes:

[Journeyman]

Good day, I came across a secondhand Canon 25mm extension tube at fair rice. It made possible a chance to check the options of teleconverter linking.
I hooked up:
lens - 1.4x - 25mm extender - 1.4x - camera Canon 90D
The test photos were spot on over 10 metres, the setup worked very well as a long lens with very tight focus on plant leaves and stalks.
The test on the moon shot was dismal at best. No focus available with infinity settings, on either my Canon 400 prime or Tamron 100 - 400.
The outcome has been to give me a good macro effect on my 18 - 400 Tamron. Not a completely wasted effort, it was something I had thought of doing.
Time to follow Ameerat’s advice and take time to develop available shots. I have a series to process, I will post them in due course. Regards JM :o

[Journeyman]

Good day, is there any engineering or electronic reason not to connect a Canon teleconverter to a Tamron lens? I found (in error) that my Canon 1.4x fitted my Tamron 100-400 cleanly. Today I tried the combination and it seemed to work correctly.

A check with a vernier indicated all of the matching end dimensions were compatible.

It offered a surprisingly full spread of AF functions, the photos were good. I did notice that the whites were lacking detail, though this affected the photos taken with my prime lens also, I suspect an operator malfunction here.

Thanks and regards Journeyman

[ameerat42]

No..., because both items are made for Canon mount.

Sometimes not all functions are supported, but then even with same brands.
- And it varies from lens to lens, so that for eg only, you might not get some
function with a UWA that you get with a telephoto, or v-v.

So, that everything seems to transfer through the TC is a :party6:

[Journeyman]

The only odd thing I found is the image data shows 800mm length rather than 560. Thanks for the info.

[arthurking83]

The only odd thing I found is the image data shows 800mm length rather than 560. Thanks for the info.

That would make sense.

400 x 1.4 = 560 x 1.4 = 784 (close enough to 800mm) :th3:

[ameerat42]

The only odd thing I found is the image data shows 800mm length rather than 560. Thanks for the info.


That would make sense.

400 x 1.4 = 560 x 1.4 = 784 (close enough to 800mm) :th3:

Some cheap-on-chip rounding algorithm :p
Mine shows exactly dbl the FL setting with the 2X converter on :cool: