ARE EXTENDERS WORTH IT? I tested 3,000+ pictures to find out!
I tested 3,000+ pictures using a blur detection algorithm to determine the sharpness and autofocus accuracy of a teleconverter. Check out the results!
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** TRANSCRIPT **
Kevin Raposo here with speedyphotographer.com, and in this video, I put together the ultimate answer to your simple photography question: should you use a teleconverter, or should you crop your pictures instead?
In this video, I put together the ultimate answer to your simple photography question: should you use a teleconverter, or should you crop your pictures instead?
We’re going to compare if your pictures will be sharper or softer with a teleconverter, and we’re going to compare if your autofocus will be better or worse with a teleconverter. And throughout this video, I’m going to ask all of you to try guessing which ones are which,
Essentially, the algorithm can scan any picture for sharpness to determine if the subject is in focus with a 98% level of accuracy.
The sharpness of the picture is then given a rating between 0.00 and 1.00. A rating of 0.00 means the picture is extremely sharp, and a rating of 1.00 means the picture is completely out of focus.
In case you think this is impossible or complete bullshit, here’s a quick example: this picture got a rating of 0.22, this picture got a rating of 0.91, and this picture got a rating of 1.00. Pretty straightforward!
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** CHAPTERS **
0:00 Introduction
0:38 How the Algorithm Works
1:40 Sharpness
4:11 Autofocus Accuracy
6:29 Test Limitations
7:19 Conclusions
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** TAGS **
teleconverter canon,teleconverter sony,teleconverter nikon,teleconverter,extender,camera,A WARNING to All Photographers: DON’T BUY A TELECONVERTER!!!,Teleconverter Pros and Cons,Teleconverters: Is the extra reach worth the penalties?,Canon Teleconverter - or should you just crop your image?,All About Teleconverters (TCs)
Very thorough in your study and presentation; so awesome job! Thank you and take care and be safe out there….
thank you, I appreciate it!
Great job! Will have to look at that lens too. Thanks.
glad you enjoyed it!
That's good to know, thank you for providing. I use the RF2x TC with my RF800 f/11 for lunar shots and I'm very happy with the details.
it doesn't surprise me that you're happy with the detail. considering that a 1.4x teleconverter was already sharper than cropping, I would expect that difference to be even more significant with a 2x teleconverter (even though I didn't test it)
I have been looking for a quantitative comparison like this for months. I can't believe the algorithm took this long to recommend you! Just awesome. I especially like your tests under multiple conditions to average out random differences. Any thoughts as to why TC sharpness was better in your manually focused images but worse with autofocus? I might have expected improved AF when there were more pixels on the subject, especially when the lighting was good. PS: a new subcriber and about to binge :)
Appreciate the kind words and glad you enjoyed the video! It’s been a while since I put this video together, but if I remember correctly, I speculated that manual focus was better because I was able to fine-tune my adjustments to the best of my ability
Auto focus accuracy is expected to worsen with less light coming through a lens. This would be true even without any teleconverters, for example an f2.8 lens should focus better than a f4 lens, because camera gets more light to work with to figure out the correct focus.
You're not wrong about that, but one could also argue that the shallower depth of field at f/2.8 might lead to more out-of-focus images. It's impossible to perfectly measure, this video is just a best estimate
Great study, Kevin. thank you for the data.
Forgot to add that some bodies w a teleconverter will limit the autofocus to certain f-stops, so another reason to beware of conditions when using a TC.
thank you! and you're correct, that was another factor I didn't account for in this little experiment.
@@kevinraposo great job on this Kevin. 👊
I was looking for the word, "native". Typically teleconverters work the best when totally the camera/TC/lens are the same make. My Sigma TC/lens is works well on my old D700 but not nearly as well on an FTZ converter using AF-C. Nikon is famous (or infamous) for new models not playing well with 3rd party, but work great with native legacy gear.
I've got the Pentax HD DA AF 1.4x AW Rear Converter and I love it.I use it on my Pentax KP, often with the 55-300mm PLM. I've not ran a scientific test but I've not been unable to notice any loss in quality at all. I was previously cropping in and I wasn't happy with the results, hence my purchase. Ever since getting it I've been really happy with the additional reach and the image quality is great. I chose this particular teleconverter due to the reviews, especially on Pentax Forum's. The general consensus was there is no loss in quality and that images remain pin sharp.
That's good! Results will obviously vary from camera to camera, my experience and data here might be different from yours
Thanks, best video on this subject in KZheads history... I have been searching/looking/searching/looking and they are all "a bit bla bla", but this video is short, concise, factual, and just what a photographer needs to know, nothing more, nothing less... 100 out of a 100 on this video... thanks again
thank you so much for share your experience that's so helpful
Glad it was helpful!
I’m shoot motor sports with canon 600mm f4 lens. With canon 1.4 converter I nail much fewer than without converter but the ones that are sharp are worth the risk.
I am stuck debating to myself whether I should buy the Nikon FX TC-14E III 1.4x for my 200-500mm f5.6 lens for wildlife photography. Reason being is I hear in lower light conditions like overcast it struggles to focus on moving objects, especially if they are small and fast. The other option is for me to buy a used D7200 for that 1.5x crop sensor factor and use it with my 200-500mm so it appears as if I shot it at 750mm without losing any f stops, since its just capturing a smaller portion of whats coming through the lens. The D7200 used being around the same price as a 1.4x teleconverter brand new. But I am unsure if the image would be as sharp with the D7200 compared to using the D750 with the fx lens in low light since the ISO performance of the 7200 is nowhere near as good as the full sensor D750.
Wow, this is what I have been long for. I cant decide if I should get one or not. Thanks for helping me make a decision.
I have always found 1.4 converters very useful tools, with little loss of image quality. On the other hand, I have struggled to get a sharp image with a 2.0. Locked down tripod, remote, doesn't matter. Soft. If I need maximum reach I find the combination of a 1.4, APS-C and perhaps a final small crop in post to be most effective.
Useful. Thank you.
I appreciate it, glad it was helpful!
This is a great review, but what’s the name of the app/service for the sharpness comparison algorithm so we can run our own tests?
Thank you Kevin! do you use any software to determine blur detection algorithm on list of images? I would like to run through my images to see how well I have done :)
I think you're asking me how you can run the algorithm yourself - you'll need to download the free script online (I provide a reference at the bottom of the screen at 0:21) and run it through MATLAB (data processing software).
@@kevinraposo Thank you Kevin! I looked at and found documentation around OpenCV and I was able to write the code :D ..I learned something new today :)
I had the Sigma 150-600mm Canon to Sony using the Sigma adapter on the A7iii and the adapter I think made things worse with a teleconverter because metadata for lens was wrong, AF worked with the 2x real good. One thing when using teleconverters on Canon/Nikon is the f/8 problem when above does not work, I tested on my Canon T2i and it was true. The testing needing much time both for shooting and processing make testing the many models of cameras and lens kinda impossible. When I upgraded to the Sony 200-600mm along with 1.4x and 2x I went out to test AF on the moon from 600 to 2x 1200 and APS-C 900 but also 2x in APS-C for 1800mm AF was fast and sharp and to boot handheld tracked flawlessly where the instruction booklet said above f/11 would be slow. I would say stick with brand lenses if AF is of concern and know about the f/8 problems. The Sigma was good for me when I had it but was a year or so before the Sony came out.
Thanks Kevin, I would love to see the same experiment conducted with a 400mm prime with both the 1.4x and 2x teleconverters
maybe in a future video! glad you enjoyed it
Not a bad test, you got quite a nice method, good exaples and you acknowledge the limitations - but there is one more thing to consider, the R6 is fairly low resolution camera for today's standard - with 1,4x crop you get about 10 mpix photo.... this could be very different with R5 where you still would have about 22 mpix after cropping - that could do a real difference in sharpness, especially when you consider using native RF lenses like 70-200, that are significantly sharper than EF lenses... From my experience - I'm using the R5, FR 70-200 f/2.8 and Sigma EF 120-300 f/2.8 shooting the classical music concerts. Using f/2,8 I get exposure about 1/200 with ISO between 1600-2500 (not ideal speed, but I also have to deal with flickering lights) - using 120-300 with 2x TC works, the pictures aren't bad after being processed, but it's actually better to use the crop, since I can keep lower ISO... Speaking about the final exported image - comparing the Sigma 120-300 at 300mm and the cropped RF 70-200 after exporting to final resolution (mostly 1920px on the longer edge) the RF 70-200 have a bit of an edge even through the resolution loss - the combination of optical IS and IBIS and better optical resolution works quite good - I mostly choose Sigma for better reach (possibility to crop even more) But I acknowledge this is quite a specific scenario of shooting in the relatively low light situations...
You are correct, results may vary with different gear. I would have liked to use the Canon R5 for this experiment just to see how the results might have been affected, but unfortunately, I didn't have the time. Thanks for watching
i've been considering getting the Sigma 1.4x for my Sigma 100-400 lens. Can't decide yet whether it would be worth the $200 (used) cost. A part of me feels that teleconverters were more useful back in the days of film when it wasn't so easy to just crop a photo. I mainly just want it for shooting photos of the moon.
I really liked your video. Your approach is well considered, but I think more work should be done. For instance, would it matter if the lens, teleconverter and camera were all of the same brand? Is there a difference between camera brands? I've found that my Canon R5, Canon lenses and Canon teleconverter can produce very sharp images in good light, not so well in other conditions. Cropping images that have been made with a teleconverter can work very well in the right conditions. Thanks, Kevin. I just subscribed.
Appreciate the thoughtful comment and feedback, and glad you enjoyed the video. Thanks for subscribing!
Hi, could you post a link to the blur detection code / software you used ?
Reference is available at 0:21, bottom of the screen.
Very interesting. Can you have another video testing the Canon RF 1.4 and RF 2 teleconverters. Different teleconverters will give you different results. Thank you.
Hi, my 70-300 is soft at 5.6 so I have to set it to f8,my question is, when I put on my 1.7 tele does the tele just lose me the light of that amount of stops or does it actually step down the aperture? Do I still need to set the physical aperture to f8 for sharpness then have the lens add another 1.5 stops of light loss, or has the tele actually lessened the aperture and therefore increased the sharpness for me?
Dont know what camera you used. In my experience cropping from 45 mpx is sharper cropped than using a tele. Interesting though,
When you downscale an image doesnt it sharpens the image?
? ( Maybe I'm wrong ) alow the apparent Fstop changes when you insert a teleconver, the depth of field remain the same ( i.e the lens aperture isn't altered because you insert a teleconver ) . Hence your f2 + + 2x teleconver is now passing equivalent light to an aperture setting of F4 but still has a depth of field equal to it's aperture sitting .. Am I wrong or correct.. 🧐
I can say that you can get some absolutely beautiful and very sharp pics with a 1.4 tc on a 600mm f/4 mark II canon, probably better then my 100-500 at 500mm🙂
hi sir pls help me.. my sony camera alpha 3500 is it posible my smart camera i make extra monitor
Watch my other video on this topic for information
Something I have heard is that a sharp lens is necessary for a teleconverter. Imagine a lens that can only reproduce 12 effective megapixels. When you enlarge that image, you are also enlarging the lens imperfections. Which makes sense to me, but I have not seen a scientific text of that theory. A faster lens autofocuses better, and at some point (usually between f8 and f11) you ought to switch to manual focus. There's a reason people pay ludicrous amounts of money for fast, long glass. It works better (while breaking the bank and giving you a fantastic workout).
Most people say negative things about teleconverters. Did you know that Fuji X-T5 has a digital teleconverter. ? Putting a teleconverter on their 100-400 mm and using the the digital as well would be interesting. Thanks a lot for the video.
Digital teleconverters just crop. Same thing for digital zoom. Optical zoom is clearly better. You're just throwing away pixels. Of course, you do that when you crop an image too.
This is great
glad you enjoyed it!
I got the last picture wrong. lol I picked the no tele converter thinking it was sharper.
Result really surprised me man..😅
Can a Sigma 2x converter work on a Sigma 150 to 600mm?
If you tried the sigma, Sony and Canon and Nikon… I could buy this. I mean I accept your results FOR that setup.
I think these results would be similar across different brands, the lens physics are consistent - but yes, fair enough
So basically it all depends on the situation and use case. And also your base lens, if it is a shit lens you'll always get shit results. This video clarified my doubts.. I've bought a 750D today and it comes with 3 lenses and 1 teleconverter, was 300£/330$ so was kinda nice deal for what I need. Will be testing out all the gear and hopefully the converter will help me out when I visit the zoo to get nice up close images of the marvellous animals 🥰
Love it! Basically, if you start with shit and magnify it, all you get is magnified shit!
The teleconverter increases magnification, and therefore produces blurrier backgrounds. This would lead to less detected sharpness in your algorithm. More in-depth analysis would be needed to see whether this merely weakens your second argument, or refutes it.
The algorithm is uneffected by the blurriness of the background. It works by analyzing edge sharpness. If you review the example at 1:17, you'll understand what I mean. The fence behind the player becomes increasingly sharper as you look from left to right, but the algorithm correctly detects the edge sharpness decreasing as the player is drifting out of the focus. As a result, a higher value is assigned.
@@kevinraposo Can you share the name of the algorithm, or paper/publication? I'd like to learn more technical details about it.
I provide a citation around 0:21 at the bottom of the screen if you're interested
@@kevinraposo I missed that, thank you!
How many did you get right? Let me know in the comment section below! To join Speedy Photographer or watch my FREE training: www.speedyphotographer.com You can follow me here: instagram.com/kevinraposo instagram.com/speedyphotographer
By the way our disconnect is that people with KZhead channels sometimes assume they are the experts and teaching others. It’s a form of confidence biased teaching and it’s easy to get stuck in that, I know from personal experience trust me. There’s lots of people online who are completely wrong and yet feel they are “experts!” You obviously know what you’re talking about, I think you’re just not to pleasantly surprised a few people know more than you. Or have even more experience than you do. Sometimes the experts need an expert. There’s a reason Tier 1 US Military units train so much, despite being the dream team of SF. You can never know enough when it comes to most things in life. Someone always knows more and it’s okay to be wrong or not consider everything, especially if you’ve not owned 20 super-telephoto lenses like I have. I love learning and I think you do as well, I’m not calling you out personally. Just something I see often on KZhead. We could all learn more. No matter what we think we already know!
@@patricksmith2553 I have no problem with acknowledging that other people are much smarter or knowledgeable than me. I would be ignorant to think otherwise. I made this video with the full expectation that it would be criticized for a variety of different reasons, and I always find it interesting to learn where I went wrong. But most of the criticisms have come from people who misunderstood how the blur detection algorithm works, or think my test is invalid because I only used one lens and teleconverter. This video took me over a month to research, shoot, test and put together. While I have used many other super-telephoto lenses over the past ten years, it is unrealistic to expect a single photographer to dedicate that much time and energy to testing every possible combination of gear. This video was intended to be an interesting experiment based on academic research, and nothing more. With that said, I appreciate you taking the time to respond.
@@kevinraposo I apologize for coming off rude or sounding like a jerk. You genuinely seem like a nice guy. I think maybe your video and test were not really well thought out or well researched. Your test and video would be really handy for Sigma users or people who have that combo. However I felt like it was mostly limited to that type of scenario. My results with my teleconverters are completely different, I only lose 3-4% sharpness with my combo. Other tests have shown lenses and combos like your's can lose as much as 30% of their sharpness and thats before I get into the massive AF hit you take. I don't any loss in AF speed with my 1.4x on my f/2.8 or f/4 long glass. But add a 1.4x to an f/6.3 maximum aperture lens is going to kill your AF speed and accuracy, frame rate, etc. So I and other's sort of feel your video is just a bit specific and not relevant to many of us. Whereas Steve Perry and a few others have done more extensive and more useful video's on Teleconverter's, that apply to a larger audience and touch more on the positives of teleconverter's. Your video sort of makes beginner's believe teleconverter's are a waste of time and money...and that's just NOT true at all. You should not mislead people who do not know any better. Outside of my subjective feelings on the video, I can see you're a good man and a talented person. It was never personal.
4 of 5
Testing at the same conditions is thorectically correct but not practical. In reality when a TC is used a higher ISO or a slower shutter speed follows, thereby degrading the PQ. That might be the reason why the pics taken during the soccer match were sharper WITHOUT the TC
🤣 I score perfect. Guess right all the pictures
good job!
"Make sure your video is set to 4k." Only gives the option of up to 1080p. LOL
Video was uploaded a few hours ago. KZhead takes up to 24+ hours to process 4K version. Check back in the future.
Sorry to be frank, but you’re either completely wrong or it’s a pointless test really, I’m not sure how I land lol. First of all every lens and teleconverter is slightly different and you’re testing a relatively cheap zoom lens from a third party manufacturer. Also you’re leaving out the fact that teleconverter’s magnify the image, they also can help with “subject isolation” or background blur when used at or near MFD. Your minimum does not change, therefor you’re actually getting more focal length or a larger maximum reproduction ratio. Lastly you’re sort of skirting around the fact that you can do both, I like to use my Nikon TC-14E III 1.4x TC on my 500mm f/4E VR FL to achieve 700mm f/5.6 and then be able to crop afterwards thanks to my D850/Z9. Meaning DO BOTH, you can crop and use a teleconverter, which can’t be achieved by just cropping more. These are extremely important issues not really or fully laid out. You obviously brought up these points but overall I feel it’s a misleading an ridiculous test, because people think or say your test discovered or proved something…and you did not. So thank you for your time and effort, I’m just not sure this is helping people!
Respectfully, I disagree with your first two points. First: I used a $4000 lens, arguably the best third-party super-telephoto on the market. Most consumers (and even professionals) would not define that as cheap. Second: The algorithm works by calculating edge sharpness, not the strength of the background blur. If you review the example at 1:17, you'll understand what I mean. The fence behind the player becomes increasingly sharper as you look from left to right, but the algorithm correctly detects the edge sharpness decreasing as the player is drifting out of the focus. As a result, a higher value is assigned. Your third point is valid.
@@kevinraposo Well you’ve never read or seen anyone say that a teleconverter actually improved sharpness like I have. Normally it does do the opposite. But it depends on to many variables such as the quality of the lens to begin with, the quality of the converter itself, and the weather or atmospheric conditions. With a big prime like the Nikon or Canon 400mm f/2.8’s or the new 400mm Z with a newer 1.4x TC converter…you only lose maybe 3-4% of sharpness. I’ve used almost every super-telephoto lens from both Canon and Nikon over the years. It’s a well known and established fact a $12k prime is near perfect optically, it gets no better. So comparing a Sigma super-zoom that are known for focusing issues…is a sort of ridiculous baseline. You might be losing 20% of sharpness and suffering some AF issues. I agree that it’s usually better to crop, but only if you have a great camera and lens, plus lighting or distance, etc. Normally if you can’t fill the frame, you probably should not be adding a TC or cropping at all. You should try to get closer or just give up. But cropping anymore than say 25-30% is going to result in more noise, less dynamic range and other issues like loss of fine (feather/pattern) details. The only reason I own two of Nikon’s latest TC-14E III 1.4x TC’s is because they are incredibly impressive and useful. I have two because I sometimes want one on both my 70-200mm and 500mm lenses at the same time. So I don’t think we totally disagree or anything, but you could have done a little better job at explaining the possibilities or positives of teleconverter’s. As they actually stretch the image (circle of projection) they obviously can have wide disparities based on lens/TC combo’s! Your results with a Sigma super zoom might result in a big loss of IQ and AF ability. Whereas I lose less no Af speed and basically zero IQ. Look up the photography life reviews of different lenses with teleconverter’s or LensRentals. My lens was tested to lose only 3-4% of sharpness, 10% loss contrast wide open, and I see zero loss of AF speed or accuracy with the 1.4x! So I can either shoot at 500mm f/4 or 700mm f/5.6 and or shoot at 1050mm equivalent focal length with a 1.5x crop on my D850. So yes that’s my main argument, using both methods. One in camera and one in post, like using a CP filter and using gradients in post?
Dxomark shows that the Sigma 120-300mm F2.8 DG OS HSM S Canon lens has a measured sharpness of 32 perceptual megapixels. Sharper than the Canon EF 500mm F/4L IS II USM at 31 megapixels, which is $9500. Sharper also than the Canon EF 300mm f/2.8L IS USM at 29 megapixels which is $6000 new. And if it can make a crappy lens sharper, then so much the better. That Sigma lens is legendary for sharpness for a zoom lens, clearly leading the category at one point (not sure if it's still true).
Of course the photos w/tele were worse... you shot as if it didnt exist. To get good results with it you need to know when and how to use it.
not clear as to what point you're trying to make here. how exactly did I shoot as if it didn't exist?
@@kevinraposo you just shot stuff as you'd normally would and slapped on a teleconverter.... that's not how the lens works.... You don't use a focal range extender (that's what we called them in college) unless you need focal range. You only use them for the most extreme distances when cropping makes the image feel too distant. Your test is 100% redundant. The question should be WHEN to use one, not whether you should just slap one on in your normal use case scenario.
A better comparison would be to have a second photographer capture the same action at the same time.
I addressed this in the video, it would be logistically impossible. How do you ensure both photographers are capturing the exact same subject at the exact same time? How do you account for human error when shooting at super-telephoto focal lengths? How do you deal with camera and lens response inconsistencies when attempting to autofocus? Shooting with two photographers would result in a much more similar set of images, but I analyzed thousands of pictures, not a few dozen. It doesn't invalidate my test results
BS
thanks!
Hi Kevin, very interesting experiment on teleconver, useful informations and as always, very well done thanks! @frame25_ren