Many will probably ask why I didn't test a Novoflex. Short answer, I should have. I didn't discover them until after the testing was done on all of these adapters. I hope to try one soon and do a follow-up video.

Wouldn’t say ur 50mm video was meaningless. But the way you took that criticism was very professional and you even made a video for it. You are a true professional and as always you have educated me. Thanks mate

Contrary to what you said, I would say it actually does have a huge effect on whether you are using a full frame or APSC. Any tolerance differences from an adapter won't be as noticeable on a crop sensor, since the outer portion of the image circle where problems are much more magnified is cut off. The degree tolerances are off get magnified towards the edges, and using an adapter on a crop sensor will be much more forgiving where problems will be significantly more noticeable on a full frame sensor.

I own a Fuji X-T2 and just purchased 2 pentax mount auto sears lens (a 50mm and a 135mm). I was getting blurry images on objects beyond the maximum focus distance. After watching your video I realized that it probably was the adapter. I had it machined 0.5mm and... voila! The results are amazing. Thanks for your video. I've probably would have never guess it. Greetings from Mexico.

Excellent job on the FFD explanation, Andrew. I have to admit I'd never considered it in relation to lens adaptor accuracy. I need to get measuring!

High precision explanatory videos like this are why I love KZfaq. Nice work, man! :)

Thanks for a clear, well informed and instructive review on adapters and legacy lenses - your delivery was professional, easily understood and timed for viewers to catch and understand salient points described - much appreciated

Thank you Andrew. I love your videos and your channel. You are always honest and humble, informative and interesting.

Thanks again, great video as always! It's wonderful that you respond to critics the way you do, by admitting error and addresing it... I only wished everyone would be as positive about improvement that you are :) Also, I can't wait to see that metabones-focus video; I shot my first wedding yesterday and had more trouble with focusing that I anticipated, so I'm definitely gonna take notes when your video is done hahaha ... Having so much trouble made me think of either the 16mm1.4 or getting a full frame, but I hope the speedbooster could do the job

Thank you Andrew, excellent comparison for us lovers of vintage lenses. One thing to keep in mind is that the study included one adapter from each manufacturer, i.e. test sample size was one per vendor. Most likely each manufacturer has different quality control protocols which could result in a wide range of finished product dimensions from a single brand due to varying manufacturing and assembly tolerances. Another comparison criteria which might be useful for some users is adapter performance during long exposures. From my personal experience I have been using vintage Minolta lenses on Fuji X cameras for the past three years. With regard to adapters I started with Fotodiox which turned out to have significant play at both the camera and lens interfaces as well as visible light leakage around the adapter release push knob. Next I used K&F Concept adapters which were excellent in terms of mechanical fit and controlling light leakage. However the adapter was damaged while using a 200mm lens attached to my camera which resulted in a loose adapter interface (damaged retaining springs) on the lens side. I ended up purchasing a Metabones adapter which has been serving me flawlessly over the past two years for long exposure and night photography. Thank you, and keep up the great work!

That is quite shocking actually. Though I always suspected there to be a difference I couldn't imagine them to be so significant. Thanks for this video.

Great info. Just ordered Fotasy and will test with my Super Takumar compared with my K&F.

Great video!!! You helped me make an informed decision and thank you for your videos.

Thank you, I learned something today.

Fascinating and thorough! I had not considered that manufacturing tolerances would be off enough to affect that. Very good to know.

Looks like you went to the Harbor for that micrometer. Great video man. I love it when product gets compared like this.

very informative Andrew: There is another even more important issue when the adapter is not well calibrated to infinity. Quite some lenses like the Nikkor AIS 28mm f2.8 / 2.0 , 24mm AIS f2.8/2.0 , 20mm AIS f2.8, Tokina 90mm ATX f2.8, et cetera some Tamron SP lenses like the 90mm. Teles with internal focus. Lenses use a close range correction mechanism or a doublet at the back to conquer spherical abberation when you focus close up. So when an adapter is a bit off, this severely impacts the quality at any distance for these lenses with a CRC mechanism .

Great test. I will be testing an FD to EF vs an FD to RF adapter soon...

"Kindness before cameras" is an awesome closer. :)

This was a super interesting video and I'm glad you did all this testing. With that being said, I'm going to keep using my no name ebay adapter because I personally don't care at all about the slight imperfections haha

Most interesting and very systematic research! And amazingly pleasant, friendly and discussion-geared presentation - love your style! Am I going to get better adapters or use more modern lenses. Likely not. The result is relevant for photos towards a wall, sensor parallel to the wall. Or similarly placed objects. When taking photos of walls, I would avoid this constellation, to get more interesting perpectives. As I am use vintage glass mostly wide open, very selective, slightly softened focus, there are no worries for my personal shooting style. I also wonder, complex lenses are developed in order to achive optimized performance in the corners of test charts. How little does this have to do with real live challenges for lenses

Interesting idea for a video. I have one Nikon incoming lens that I'll be using on my Olympus om-1 mark III. You've highlighted a problem but only for Nikon lens on a Fujifilm TX. There are so many variations to test before you could accurately make an assessment of any particular adapter manufacturer. But you have shown what to measure and a simple test and there is a potential problem. Thanks for that.

Oh wow, Fuji specifically mentions infrared for some of their stuff? Intriguing, to say the least... It's definitely nice to that there is a difference between the various adapters.

It's funny that I was wondering about a lens adapter i have and you just happened to review a Nikon lens with a Fuji mount. that's exactly what i'm doing. lol

Love the disclaimers on fuji or FF :p

I blindly ordered one of those fotasy adapter for my xp2. Glad i did that

Just picked up a tilt adapter by Hersmay. 10 degree tilt and 360 rotation on the fly. It was $23 on Amazon. M42 to FX.

It's not just the edges. There is a noticeable difference in sharpness and contrast between my Novoflex and K&F adaptor at the very center of the frame. I believe it is because the inside of the K&F is shiny where the Novoflex is matte. Stray light must be bouncing around in there. I don't what else it could be... I thought expensive adaptors were snake oil- since it's really just a metal tube, but apparently not.

Phillip Reeve wrote a good article on lens adapter tuning. In short, you can fix some adapters for some mounts, nearly all of which err on the side of being too short, by shimming the mount ring. On adapters for Olympus OM lenses, the lens-side ring can be unscrewed, and layers of a thin metal (e.g. kitchen aluminum foil, or self-stick copper tape) can be added as a spacer. On my adapter, a couple rounds of shimming and testing got my lenses to come much closer to focusing at infinity when at the hard stop. I also tested some resolution charts, and some of my fast wide primes (I think with floating elements) actually did improve in overall flat field sharpness (when manually focused) as a result - since the focus field curvature was lessened. I stopped short of shimming it all the way to a hard stop infinity focus, as it was requiring too many fiddly bits of foil; will try again later with a thicker spacing material.

I used novoflex adaptér in my opinion the best one. You really see the big difference in long exposure shooting.

well done and appreciated. I have a Nikkor 28 3.5, 35 2.0, 50 1.4, 85 2.0 and 135 2.8... all AIS. They were given to me years ago and I almost sold them since I didn't enjoy using them on my Nikon DSLRs. New life with my X-T3! Have the Gobe adapter and the Mitakon Speedbooster. I plan on keeping both regardless of test results but it's still nice to know.

All tough i appreciate the effort i think the conclusion is wrong. Only when you are taking pictures of a perfectly flat subject which is in a perfect right angle to your camera is it of significance if the focal plane is aligned correctly! If the focal plane bothers people that much you should use tilt shift adapters, (that's what is standard on my camera) Which is to say it is only of importance when copying a drawing, a picture, or taking a photo of a negative. even if taking architecture shot of a facade this does not apply, you don't know if you are at a right angle to the facade. I thought this video would be over internal reflection or light leakages. which does affect real photo quality.

Oh man, the timing on this. I recently got a K&F Minolta to Sony E adapter and while I watched this the delivery person dropped off a Viltrox Nikon F to Sony E adapter. First thing I did was find my caliper. :-) Thanks for the info.

I'd love to see the lens test made with the TechArt LM-EA9. It can extend to dinf the perfect focus. That should fix a lot of the distance issues. I'm getting one soon and will check differences of each side. For most lenses it needs a second adapter though (to Leica M), that might introduce more skew.

I was literally looking for comparisons of speedboosters for my XT3 last night! It doesn't really seem like anyone's done a good one so far, looking forward to seeing that video! As a note, I don't know if it's an issue for Fuji, but I used to get some crazy flares from certain adapters on my a7s. It turns out the inside was black, but still glossy, and it was reflecting the light off the inside of the bayonet onto the sensor. I ended up ordering an adapter with a square inlet and flocking, which helped a lot. I don't know if this is an issue on Fuji, as I haven't seen it so far, but it may be worth considering, also a real potential concern on the speedboosters too!

Thank you for this. Appears to be very sound logic. (appreciate following up with your adding the perspective that this is only a sample of quantity=1. (which was enough data for the poor performer, but not enough samples/data to confidently claim championship status among the top performers.)) personally, I would have just assumed that this area you measured would have been near perfect. Why did the manufacturer mess up on this dimension, which is so critical !!! other than sloppy work, hurrying the machining process, not bother to measure and discard what is off, or have very loose standards for what is acceptable.

First of all, Dearly thank you for this great job you executed that should be priceless for many who understand and are in need in this very revealing field of photography. Having said that and the fact that I can't thank you enough for that, please allow me to point out a few flaws in your review, only to be constructive critiques for the sake of a better future and not any God forbidden troll or likewise. I see you love your Fuji and had a 50mm Nikkor to test but honestly, 50mm is too light a lens and gravity talks big here. Besides the logarithmic importance & prominent effect of the long FL (Focal length) lens to show and magnify the flaws of a badly made adapter. A point you may want to consider on future tests. 1:53 Oh no. I'm not a fan of FF alone, as I do shoot all the time, both with all kind of sensors and like APCs, especially the petite of all M4/3 but the new high rez, high pixel FF sensor do show the flaws in the build quality of adapters, much more significantly or prominently. So here, the choice of Full Frame sensor could make a difference. That is besides some other problems s.a. Canon 5Ds that have apparently Trump type mirror (Bigger size (Physically-not mentally) than others!!!!) so the mirror gets stuck to the back of certain badly made adapters while shooting!!!😱. Yes, you may have no problem with the longer flange distance of your mirrorless Fuji but others do have significant problems in this department that you totally missed. So maybe of note to add this to your future tests and good recommendations for the sake of perfection as I know, that is your sole aim. 8:31 You confuse the viewer at this point. If ever you make a revision ever, make a revision also at this point for better understanding. 4:26 I wish but sorry if I have to disagree on this. As a person who has very many adapters, I have seen some really really badly built ones, even some that due to no quality check, some copies of the same company, misses the infinity focus when another copy not (And they were all promised to focus infinity). This is beside the wiggling ones that you can potentially miss the section of focus due to gravitational pull of lens and worst of all.... God damn them! One company that had made such a bad lose adapters for Nikon (Bad latch design that doesn't engage any more overtime or even some, right out of the box) that won't lock when attached and my very expensive, always petted Nikon CAT 500mm F5 ( the Nippon Kogaku 500mm F5.0 Reflex Nikkor Mirror Lens), accidentally fell off the camera, that's when I was trying to focus for stars in a dark night and of course, as bad things happen, this had to be in front of 17 steps of the staircase and so did my baby tumbled all the way down!!!!!!!! I guess you guess how much I hate them! TG lens stood the insult but my heart is broken. Bottom line. Pay a bit more or go with the unbiassed genuine reviews so you don't be SAD or cheated at the end. 13:39 TOTALLY agree with you on this extremely important point. The main problem with any product coming to form China or the far east (Except high-quality Japan's products and some of the So Korea products) is truly that lack of QC or Quality Control and one sample (UNFORTUNATELY) is not representative of the entire batch of the product! This would explain the cause of many arguments some of your viewers may come within the comments as their inference may be quite right and opposite to what you expressed here but that could simply be due to receiving a better random copy rather than what most are! Again thanks for making this very nice, useful review that I found very informative. (Side note: Please secretly let me know your eBay user name to add it to my black-list of sellers I must avoid🤣 16:58) But appreciate your honesty, A typical good American. So please Everyone VOTE for the better of our great land...Nov 3rd is almost here... GBA.

Yes adapters can affect image quality specially on edges. I have seen a comparison in KZfaq of the mc-11 vs metabones on sony and the difference was clear

Well I'm happy I don't need to go replace all my fotasy adapters now. It's definitely an interesting question

This was great, I didn't think such small differences in tolerances had noticeable effects. I may need to re-evaluate my adapter collection. Something that you should know though (if you don't already) is that vintage lenses with floating elements will be more effected by the slightly shortened flange distance of these adapters that allow lenses to focus beyond infinity. An example of a lens like this is the AI-S Nikon 28mm 2.8, which has a floating element design that Nikon has branded CRC. With this lens the adapter must add the exact extra flange length or lens performance will be reduced.

The difference between the high and low points on a circular part is called runout. Ideally it would be zero but in the real world there are tolerances. The better parts have tighter tolerances but the price goes up by order of magnitude. A 0.1 mm versus a 0.01 mm tolerance in many cases is literally ten times more expensive as you have to pay for new tool bits and have a higher reject percentage to absorb. This is why Leica lenses are so unbelievably expensive. It's the secret sauce that makes them what they are. Incidentally it is also what makes a lot of Japanese cameras so unbelievably good, they somehow figured out how to do it faster than anyone else and the world has been asking "how'd they do that?!" Ever since the 60's. Some of my Pentax k lenses are so precise it's like they were collimated by God himself.

With Fotasy adapter, my 50 mm isn't really 50mm, it crops a lot of space. I have compared native lens with the ones im using with an adapter. It truly makes a difference.

Nice video. I have a variety of Nikkor lenses when I was using Nikon F and Nikon F90. But today I only have a FuJi X-T2... I found: - Fotodiox Pro Lens Mount Adapter that look nice, but after your comments... I'll wait - K&F Concept (look like Gutty) but available in Canada Big thanks for sharing.

So i'm impressed that you got a Mitsutoyo caliper.

Do you have any idea where these are being made? I'm curious about the process

Hello Andrew & Denae, as always congratulations for your channel and these wonderful reviews, but I have a doubt, I bought an AX mount URTH adapter to use some old Sony lenses and the adapter ring only takes 8 steps, is it normal?

Did you specify weight in ML @6:25? Grams probably ;)

Has the Novoflex been tested? I'm primed to order it ASAP for Pentax K to Fuji X. Thanks

I use the Fringer Canon to Fuji and it works great with my Canon 400mm

Great video. Thanks. I’m trying to find the best adapter for my 50mm Summicron and my XPro 2. Any suggestions where I should start looking?

Thank you

Go with Novoflex Adapters!!

Dude... what kinda light do you have setting to your left? Thanks.

...Unless the lens has floating elements like quite a few Nikon ai-s etc. lenses. So the the flange distance should be correct actually.

The question you're asking today actually has everything to do with a full frame camera these lenses are made for full frame not made for aps-c meaning their sharpness will be more affected then with a full frame camera and less noticeable of a difference

Haha, confirms what I am saying since years: the price of adapters is not proportional to quality! Wish you had one of these crazy priced Novoflex adapters tested.... Likely not better than Fotasy either if it comes to image quality.

Interesting and important video. I bought the K&F lens adapter for adapting my Nikon A1 lenses for use with my Fuji XT-3. I am generally satisfied, but with one lens (45mm f2.8) I had considerable difficulty in removing the adapter from the lens. I am curious if you considered testing the Rayqual/Kindai adapter, which is more expensive but is supposed to be of a higher quality (it made in Japan). It is distributed by CameraQuest, which according to its advertisement, "only offers precision lens adapters). The Nikon F to Fuji X costs $149. One reader said that "in general, the wider the lens, the more precise the adapter should be". Thanks

Do you know if the cheap lenses will work with telephoto lenses? Thanks

I just bought a K and F adapter from Amazon for my Minolta Rokkor lens to go on my Fujifilm X-T20, it was the only adaptor I was able to get ship to Canada. At first I did not want to buy that model because the Kand F did not do well in your test but since Ihad no other choice, I bought it. Now that it is in my hands, I took three measurements of the thickness of my new adaptor, 1.12 in, 1.16 in and 1.19 in. The difference is .07 in. which is almost as good as your best adaptor. Still I cannot tell you if I was lucky or you were unlucky or if they improved their method of production. Thanks to your video this adaptor just gave a second life to 3 Minolta Rokkor lens, and I was pretty surprised with the results although not as sharp as more modern lens, they give surprinsingly good results

Hi, i have a Nikon Coolpix B600 which has a fixed lexed cannot be replace. Is there any way i can add in the adapter to insert another lens?

Hi, thanks for the video. If we use two adapters stacked together, what are the downsides of this? One that comes to mind is less light will reach the sensor, is this true? I'm guessing FFD risk will also increase, but as you said, in mirorless that's not much of an issue. Lastly I guess weight support. Subscribed. Thanks.

The black vs chrome is a wear item. Black or plain aluminum will wear when used while the Chrome or nickle plated brass finish will remain in tolerance and functional longer. The chrome ring may be removable to allow shims if the alignment is off. Note some adapters have 2 chrome rings for wear on the camera side and lens side. Note some shops may be buying the rejected parts and assembling and selling them without the quality checks. One sample is not a good test point.. reply on other users are better ...

Hey Andrew, are you going to be testing the zhongyi lens turbo in your speedbooster test? Ive been looking into getting one for M42 to Fuji but there’s not many reviews on it out there :(

I should try a Fotasy M42 adapter with my 17 blades Carl Zeiss Jena Biotar

Thank you been looking for this, brilliantly done. Question: the nikon 12-24mm full wide, does it cover the entire sensor at 12 or any other nikon prime that wide. I do interior photpgraphy and would like to know if these adapters interfere at ulta wide nikon glass or not. Thanks for your feedback in advance. The fringer adapter for nikon supports autofocus. It would be great if you could do a ultra wide sharpeness test with the nf-xf fringer adapter! See their site on supported nikon lenses their firmware covers. Love you channel.

Can you test a wide angle vintage lens like 28mm with those adapter, is it all vignetting or only the lens I use, I use 28mm accura diamatic with cheap adapter to sony a7r mark ii.

Honestly I believe quality control issues could lead to not consistent products so deciding which is best based on only 1 sample each is not fair, probably if I buy the same brands I will get different results. In any case I believe not all is lost, all adapters comes with 4 screws on the ring housing the lens, I didn't try but I'm pretty sure those little discrepancy could be fixed by acting with the screws and probably some thread-lock (in case)... maybe 3 screws would have been easy to tweak and obtain a perfect plain. I think tollerances of around 0.1mm are present on the lens ring itself. Another interesting discussion about adapters will be light filtering in trough the (even if very little) gap between the rings, if you try a long exposure shot with a ND filter you'll find there is ligth sneaking in.

Have you tested a Kiwi brand adapter yet? I have one, but am unsure how it performs in comparison with other adapters.

Nice job, also what I would suggested is to make sure the mount screws are tight, 99 5 of those adapters are made in China and may not be tight causing the lens flange to be parallel and that's the most important factor! I got 2 Metabones adapters for a Nikon 20mm 1.8 G for astro fo my Sony FF and noticed with 1 of them the left corner sharpness was not as good as the right so I got 1 more and it was so much better!

Is it just for me links not sending me directly to the products? Seems like just first part is active :/

Thank you for the comparison video. You wrote on the weight labels “ml” but I think you meant “mg”, right? 🧐

Great review. Thank you. Question to the community: Fotasy is not sold by Amazon on Germany. Does anybody know, where I can get one for Minolta / Fujifilm adapter? Does anybody know, if maybe Fotasy is labeled differently in Germany? Maybe thats the case I cannot find one... Thnx all!

Andrew I was looking for the video of the test of Speedbosters and l Couldn't find It. Do you have the link please?

Well shit I own a Gobe M42-MFT adapter lol but I haven’t noticed any loss in sharpness. Guess I need to buy Fotasy from now own for my vintage glass

I bought a Kiwi adapter to use with a number of FDs on EOS 6D just a few hours ago. Should I have seen this lovely video first, I wonder? In other words, was the Kiwi not reviewed because it's no good?

I use the URTH 32euros Nikon G to FX adapter with an aperture ring and it works well. The issue is the aperture ring has only 6 steps, so it doesn’t even cover full stops. Another problem I noticed with my Nikon 35mm f1.8 DX is that it opens the aperture just up to f2 or f2.2. It doesn’t open it fully, but that might be a precaution to not break the lever. I’m not sure.

I want yo use Md lens to Ai Nikon, which one you prefer. please suggest

My Konica AR to EOS M lenses are super loose on the Fotasy, whereas with the K&F they fit perfectly.

i have a canon ultrasonic 35-80 mm which adaptor do i need to mount it on my Xpro 2 ?

Hi Bro Andrew, may be you could test a Sony full frame body could be the newest one the A7C sooner when released or just the A7iii or A9 and test with the only one lens of Fujinon XF 50mm F1.0 lens.

Thanks god I found you! :D Im also about to buy an X-T3, but im currently a Nikon user. I was about to "upgrade" to Sony, but after I magicially found out this 10 bit, inbody headphone output, I finally found the perfect camera between the Blackmagic PC4K and the Sony Alpha series. However, Im struggling to find an adapter, which wont reduce the image quality of my Nikon mount Sigma ART lenses. So if Im understanding your video, the Fotasy adapter is the one for me, to who adapting sharp lens is important? :D But can I buy any of them in Europe? I cant find them on european market.

At 10:43 measuring the total thickness... You should use a flat plate and a micrometer for this type of measurement. And MUCH MORE IMPORTANT: It just doesn't say anything about the consistency of the manufacturing process. 2 adapters of the same manufacture may still differ widely.

I am thinking of buying a Fuji X-T3, right now I have a Panasonic Lumix G70. Yesterday, I took one of my lenses with me and looked if it is compaitble with the Fuji X-T3 and yeah, it was not, now I don't know what adapter I would have to get. I now know that the sensor of the Fuji is bigger than the sensor of my recent camera.

I never thought about this, mainly since I don’t use speedboosters just regular good ol adapters - however I am a fan of ordering nice cheap adapters from China :3

Do a review on a canon FD to ai adapter cos I want to use the canon FD lenses I already own with my new to me Nikon 301

Nice telecaster!

Is there a difference between a 50mm mirrorless lens and a 50mm DSLR lens with an adapter on a mirrorless camera? For example Nikon z6 + 50mm Z mount lens vs Nikon z6 +FTZ + 50mm f mount lens.

I have a M42 to Canon EF adapter and also a Nikon AI to Canon EF adapter, but they aren't so bulky, they are really thin, less than 1/4 inch, are they an other type of adapter, and if they are are there any pros/cons in relationship to these bulkier ones? they were pretty expensive too, like 10 euros for the M42 and 30 for the AI. Can someone explain/clarify?

Great review and video. Ive also heard the focal length makes a difference as well. The smaller the focal length the less the light will reflect off the inside of the adapter as supposedly the longer focal length it would increase the chance of the light reflecting off the adapter.

What about original lens mount adapters? (Canon,nikon, sony and fuji) will i have a problem with those? Seems like all you tested here were third party adapters.

Have you tested several Fotasys to determine you didn't just get a good one?

If i take picture using canon ff sensor lens on canon ff sensor body, the camera will produce image exactly which fl it taken. If i take picture on 17mm fl, the image will turn exactly 17mm wide. If i use the same lens, let say canon 17-40 f4 L on sony A7 ii with adapter, if i take picture on 17mm fl, will the camera produce exactly 17mm wide image? Or maybe wider or narrower?

I bought a K&F Concept Pentax DA to MFT lens adapter recently. All Pentax lens can focus at infinity in MFT body but focus ring stop at a much closer distance than at Pentax body (e.g. Pentax DA70 focus at infinity at 5m on lens distance scale). Does it mean the adapter is slightly shorter than it should be?

Dammit bought the fotodiox before watching. Wanted it to use my 105mm f/2.5 ai-s on my xt20. Im hoping that whatever imperfections I come across will be easily corrected in post.

If the flange distance is off you also lose parfocality on zoom lenses (eg canon fd)

What do you mean by "ml" in the weight topic? Isn't it supposed to be "grams"?

What lens was the video shot on?

About GOBE one, actually it's not too bad ? I didn't understand what you wanted to say by "not red-hot". Good or not good finally ? Thank youuuu mate !

I use the $99 Canon ef to rf adapter and the Tamron G2 24 to 70mm on an R6M2 and the images tend to look like a painting in low even with a flash. I switched to an RF and dont have this issue.

Surly when you tested the lenses, they where all done on the same adapter! If that is the case, then the results of lenses you tested where as true as the adapters and as you comment at the end, the adapters will vary, as cheap manufacturing of mass products will. It’s like cutting a piece of wood with a new blade, there has to be change as the blade dulls, degradation and that is a fact. So I wouldn’t beat myself up, your both right and the only way to achieve an exact comparison, is to have each tested when you have bought it. It’s not achievable, the sam as perfection, it doesn’t exist, but a mean average or a reliable manufacturer is a good starting point. You said yourself that the Metabones was loosest and the Photsy was a little rough? So in my conclusion, unless your not happy with the result, then go with what you feel is the most consistent, remember those lenses you are using are decades old and each will have suffered the rigours of time each to a different degree. DG New Forest U.K. PS I just bought a Minolta 100mm 2.8 Macro lens for £80 and Ken Rockwell puts it as the most perfect lens he has ever tested Sony still make that lens and use the same glass and have rebranded Sony £500? Great photos on it as you do great photo’s!