1. wtf1965

    wtf1965

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    I have a Canon EOS1300D and wanted to try a teleconverter. Its a Sigma 1.4 EX DG. Now it fits onto my camera body but the front of the lens protrudes and wont allow my Canon 75-300 or my Canon 18-55 to connect.
    I can get them attached with the use of a. 12mm extension tube but I don’t notice any improvement in distance.
    Have I bought the wrong TC?
    Please advise.
    Thanks
     
  2. shotokan101

    shotokan101

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  3. wtf1965

    wtf1965

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    Many thanks Jim.

    Best see if MPB want to buy it back!
     
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  4. ecoleman

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    And not all canon lenses will work with a TC, even if it is a canon TC.
     
  5. StewartR

    StewartR Efrem Zimbalist Jr Advertiser

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    Yes and no.

    I believe that, within the Canon EOS system, any brand of teleconverter should work with any brand of [compatible] lens. For example I've used Canon teleconverters with Sigma lenses, though not the other way round.

    But the key word there is "compatible". Most lenses are not compatible with teleconverters. The reason is basically that the teleconverter would degrade the image so much that you'd be better off without it. As a general rule the only lenses which are going to be compatible with teleconverters are telephoto primes (say 100mm or longer), a few professional quality telephoto zooms (eg 70-200mm f/2.8), and some shorter specialised lenses such as macros and tilt-shifts.

    Canon (and, I think, Sigma) enforce compatibility by putting protruding front elements on teleconverters and recessed rear elements on compatible lenses. If the lens isn't compatible, the teleconverter won't physically fit - as you've discovered. There are some third-party teleconverters (eg Kenko) which don't have protruding front elements and therefore will fit any lens. But there's no point, because if the lens manufacturer hasn't intended it to be compatible then you'd be better off without the teleconverter.

    So you may or may not have bought the wrong teleconverter, but you've definitely bought the wrong lenses to use with a teleconverter.
     
  6. shotokan101

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    What utter twaddle that non-custom teleconverters cannot be used and generate good image quality......... :ROFLMAO:
     
  7. rob-nikon

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    Stuart has summed up many of the pitfalls of teleconverters. On lenses like the 75-300 they aren’t designed to fit (it’s not to say a third party one like a kenko wouldn’t fit) because they would reduce performance below what the manufacturer would deem acceptable. Teleconverters not only affect the maximum aperture (1 stop reduction for 1.4 TC, 2 stop reduction for 2x TC) but also IQ and AF speed & accuracy too. Don’t forget some cameras also have a maximum lens aperture for AF too. Isn’t the 1300D maximum of f5.6 so may have trouble wth auto focus at f8 with a 1.4TC on the 75-300 (Some higher spec camera models can AF at f8).

    As this is a question that comes up often I wrote a blog on my website about this subject:

    https://spark.adobe.com/page/pemWGeihe1GJz/


    One thing I would ask is could you crop rather than use a teleconverter? A few years ago I did a comparison and the results surprised me:

    https://spark.adobe.com/page/srrFrhs4dh3yl/
     
    Last edited: Jun 20, 2018
  8. shotokan101

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    Sorry but whilst both yourself and Stewart's posts do contain some useful and accurate information about the potential and actual effects of adding a TC to a lens I still say that it is totally wrong to imply that using a TC - whether dedicated or universal - isblikely to result in poor images - is the IQ possibly going to be less than an equivalent focal length zoom lens or prime telephoto? - Then yes but that doesn't mean it will be either poor or unacceptable.

    Of course the use of a TC is effectively a compromise but they ecidt for a purpose and provide valuable benefits to photographers

    I would also risk suggesting that a lens + TC could for some combinations actually produce better imsge quality than some longer fl zoom or prime lenses.....
     
  9. rob-nikon

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    good image quality can be very dependant on the person, one persons good can be very different to another’s. Let’s on forget the impact on AF accuracy or speed either. Third party teleconverters are fine on lenses where the OEM designed the lens not to be used with a teleconverter. Using a 1.4 TC on a 75-300 lens taking it to f8 on a camera that’s supposed to max out at f5.6 doesn’t sound the best situation for it unless you have examples of good image quality and AF performance.

    Let’s face it there must be a reason why the OEM make some lenses compatible and some not. In some ways it’s not in the OEMs interest to have their lenses incompatible with teleconverters as otherwise it’s just another missed sales opportunity to sell you yet another expensive accessory. The last few years have seen OEM increase camera max aperture performance to f8 and provide more AF point at those limits too. That’s lead to some new lenses being compatible with teleconverters for the first time (wasn’t the 100-400 mk2 now compatible with a 1.4TC whereas the older 100-400 mk1 lens wasn’t).
     
  10. rob-nikon

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    The OP has a specific lens and camera in mind which have very specific limitations in regard to teleconverters either fitting or their performance. Whilst I agree using teleconverters isn’t going to always result in poor IQ or performance (I often use them but on lenses they were designed for and marked as compatible with by the OEM) there is no such thing as a free lunch with teleconverters on variable aperture lenses on this type of lens especially if light is low and less than ideal. Perhaps some examples may help enlighten both myself and Stuart.
     
    Last edited: Jun 20, 2018
  11. shotokan101

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    Oh puleeeeeze - the reason (or at least a key reason that some manufacturers "cripple" their lenses by design is to ensure that they can get the additional revenue that forcing owners to buy their inherently much more expensive branded TC generates.
    Nect you wilbe telling me that there's a valid readon for all cameras not being able to use a generic standardised flash hotshoe in fact you can consider yourself lucky if you upgrade your camera within a brand and find that it takes the same batteries as the older model

    Regarding the podsible AF issues yes that can be a compromise but not evetyone needs to be totally dependant on AF anyway and some subjects don't really require it.

    And fwiw I own a selection of OEM TC'S and third party
     
  12. Mark twiglet

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    I generally find teleconverters a waste of time and money! I have an 80-200 2.8 nikon and found cropping better or even using the crop feature in camera
     
  13. ecoleman

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    Of course it has nothing to do with the limitations of the lens based on price. Some people want a cheap lens so these are built with limitations not because the company limit them on purpose but because those limitations simply can not be overcome at that price.

    The fact is a TC does reduce image quality on any lens, therefore the cheaper lenses will suffer more.
     
  14. StewartR

    StewartR Efrem Zimbalist Jr Advertiser

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    I didn't imply that. "Poor" is a subjective term and very dependent on individual perception.

    I did say that using a TC degrades the image. I think that's pretty much incontrovertible, though of course the key question is how much degradation. It is widely accepted that with big primes such as 300mm f/2.8 or 500mm f/4, the image degradation caused by a TC (especially a 1.4x TC) is negligible. With other lenses it isn't necessarily negligible. I did also say that with some lenses, the images would be degraded to such a point that you would be better off not using the TC, but just cropping and enlarging your image..

    One potentially important question which I haven't seen answered definitely is this. Suppose you could test all lenses with and without TCs and see whether the image quality was better with the TC or better with cropping and enlarging. If you could do that, you would have a list of all the lenses which really shouldn't be used with TCs, at least on image quality grounds. How well does that list match up with the list of lenses which are not intended to be used with TCs? One would like to think that there was a pretty good match - the reason the manufacturers don't let you use TCs is because it's really not worth it - but I have never seen this empirically tested. Maybe @HoppyUK might know?

    I think that's the wrong comparison. The comparison that we're discussing is lens with TC compared to lens without TC. We're not discussing lens with TC compared to a different lens. The OP has a lens that goes to 300mm. The question is whether adding a 1.4x TC to his lens would improve the image quality compared to cropping and enlarging. I say it wouldn't, and I say that's why the manufacturer designs it to be incompatible. Of course a dedicated 400mm lens is likely to deliver better image quality. But the OP wasn't asking about that.

    Again, I think that's the wrong comparison. I have no doubt whatsoever that a £2000 professional 70-200mm lens with a 1.4x TC will deliver better images than a £100 budget 70-300mm lens. But again, the question is whether the OP's lens is better with or without the TC.
     
    Last edited: Jun 21, 2018
  15. rob-nikon

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    I understand manufacturers do make it difficult for third party accessories to be used but in the case of the OP we are talking about a lens that can’t fit even an OEM teleconverter to it because of the protruding rear lens design so I’m not sure how this point is relevant to the OP.

    I agree teleconverters can produce good results and are valuable to photographers but like you say it’s down to certain combinations that work best. In the case of this thread the OP is talking specifically about the canon 75-300 and a 1.4TC. There is no point in talking about other lenses as if it’s not really relevant to the OP unless they are going to spend quite a bit on a professional grade lens that teleconverters were really designed for.
     
    Last edited: Jun 20, 2018
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  16. HoppyUK

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    I don't think there's any conspiracy about which lenses work with tele-converters and extenders and which ones won't.
    - TCs simply magnify the centre of the image, so sharpness is almost entirely dependent on quality of the mother lens. Most high quality TCs are broadly similar on this aspect of optical performance and the differences lay elsewhere like edge sharpness, AF performance etc.
    - TCs don't work well with shorter focal lengths because the light enters at oblique angles and edge sharpness can suffer. Shorter focal lengths also have physical mounting issues because the rear element naturally extends too far.
    - For the same reasons, TCs work much better with longer focal lengths where light rays are more parallel and there's usually plenty of room at the rear.

    Traditional wisdom is that using a good TC delivers better image quality than just enlarging the centre of the image, and that pretty much still holds true because you just run out of pixels and sufficient image area for a high quality result. If this wasn't the case, there wouldn't be much point in having telecons in the first place. But these days there are a few full-frame cameras with exceptionally high pixel counts (and without AA filters) - eg Canon 5DSR, Nikon D850, Sony A7Riii. Given a good lens, these cameras can be cropped hard and yet still have 20-odd megapixels while retaining a similar image area to crop-format APS-C camera. On this aspect, they are actually two cameras in one. This is a relatively new option that I've not compared directly (and I don't have anything suitable to hand) but I know enough to expect results to be very similar, certainly with a 1.4x TC, maybe less so with a 2x though perhaps still 'good enough' for a lot of things. Either way, a top quality lens is always the primary requirement.
     
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  17. shotokan101

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    Lots of interesting points to debate further but nobody is disputing that "putting more glass" between the sensor/film and the subject is likely to reduce the resultant IQ.

    That's forever being debated regarding the use of filters - and I don't think that anyone would really suggest that photographers should never use filters - would they ?

    Everything is a compromise and the compromise with using a TC is a slight decrease in IQ against the benefit of getting a longer effective focal length - there are as noted, other effects of using a TC such as increased minimum aperture which can possibly impair AF functions but as noted this is becoming less of an issue with modern sensors and AF systems but of course still needs to be considered in situations where MF is not an option.

    Regarding cropping vs longer EFL - sometimes that's a viable option though of course it will decrease the image resolution thus possibly affecting print capabilities - and of course if using a TC then you still have the full image resolution available for further cropping as well.

    Additionally it is often easier to focus and compose the subject when viewed using the longer EFL with a TC.

    Jim
     
  18. Phil V

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    And in this case... designing a lens down to a price which makes it incompatible with the mfrs own TC.

    Not when the camera simply wasn’t designed to AF at the resulting aperture (as in the case of this specific question)

    You seem much more keen on having an argument than discussing the actual facts of the OP. ;)
     
  19. shotokan101

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    On the contrary I answered the OP's actual question in my first post - it was you and the other Anti-TC brigade that took the thread off-topic ...... :rolleyes:
     
  20. rob-nikon

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    I don’t think any of us are anti teleconverter at all (if I was why would I write two blogs on my website about teleconverters showing pictures taken with teleconverters???), teleconverterd are great when used with the correct lenses that manufacturers say are compatible.

    The thread started off in with replies in respond to the OP’s specific circumstances of using a teleconverter with their canon 75-300mm lens then wander slightly off topic but still relevant. The facts are the 75-300mm lens attached to the 1300D isn’t designed by canon to fit any teleconverter to it. If it was canon’s own teleconverters would fit but they don’t.
     
  21. StewartR

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    Just a bit of a shame that your answer was (1) factually incorrect, and (2) incomplete.
     
  22. StewartR

    StewartR Efrem Zimbalist Jr Advertiser

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    For what it's worth, I can confirm that this is true. I've just mounted a Sigma TC-1401 onto a Canon 70-200mm f/2.8 and everything works perfectly - aperture control, metering, autofocus, and image stabilisation. I don't have any of the older Sigma teleconverters - the EX DG variety that the OP bought - but there's no reason to suppose it would behave any differently.
     
  23. shotokan101

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    In what sense?
     
  24. soupdragon

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    I have a canon TC 1.4 ver3 and coupled with my 70-200 2.8 mk2 I can see no difference in image quality.
    That said, my eyes aren't great at the best of times.

    To the OP:
    You may find information on the canon website as to which lenses are compatible with converters.
     
  25. Phil V

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    And you’ve decided I’m Anti-TC based on what?
    And I suggest you re-read the question if you think you answered it ;)
     
  26. GreenNinja67

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    I'll bet the OP is glad he chose his moniker to begin with wtf now.

    Why does someone always come along with a wasp up their arse?
     
  27. ecoleman

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    Nobody here is anti TC. We just understand that they don't work with every lens. I have 2 x TC a 1.4x and a 2x and they work great with my 70-200 f2.8 IS L. I'll also happily couple the 1.4 to my Sigma 150-600 but I'm under no illusion that they will give decent image quality when coupled with a cheap lens which is not designed to be coupled to a TC.
     
    Last edited: Jun 21, 2018
  28. shotokan101

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    That's no way to talk about the other guys.... they were only expressing their opinions about things the OP hadn't asked about... :exit:
     
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  29. shotokan101

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    Same suggested to you - see above ?

    EDIT: - I agree that yours posts have not been Anti-TC
     
    Last edited: Jun 21, 2018
  30. TonyT

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  31. rob-nikon

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    The mirror shouldn't strike anything as both teleconverter and lens should fit onto any camera fine. Its the interconnection of the lens and teleconverter due to their design. Teleconverters usually protrude slightly on the side where they mount to a lens, the lens needs to have a small recess to allow the teleconverter to fit nicely to the lens. Some lenses don't have the recess and the rear element is inline with the lens mount and hence teleconverters wouldn't fit physical together (unless you get a kenko teleconverter).
     
  32. StewartR

    StewartR Efrem Zimbalist Jr Advertiser

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    Factually incorrect in the sense that you said that Sigma TCs only work properly with certain Sigma lenses, whereas in fact they work fine with Canon lenses too.

    Incomplete (and, I would add, misleading) because by saying that the Sigma TC is the wrong TC, it implied that there is a right TC. However, for the lenses the OP mentioned, there is no right TC.
     
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  33. TonyT

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    Yup bad day, thats what i meant to say

    http://cpn.canon-europe.com/content/education/infobank/lenses/extenders.do
     
  34. rob-nikon

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