Canon RF 16mm f2.8 IN-DEPTH review: NO-BRAINER for EOS R!
Vložit
- čas přidán 30. 06. 2024
- My in-depth review of Canon RF 16mm f2.8 lens! Vs 14-35mm vs 15-35mm
Canon RF 16mm f2.8 STM at B&H: bhpho.to/2XfeZxT // WEX UK: tidd.ly/3k9l8Es
Buy Gordon a coffee: www.paypal.me/cameralabs
Gordon's In Camera book: amzn.to/2n61PfI / Amazon uk: amzn.to/2mBqRVZ
Cameralabs merchandise: redbubble.com/people/camerala...
Gordon’s retro gear channel: / dinobytes
Canon RF 16mm f2.8 sample images at www.cameralabs.com/canon-rf-1...
Equipment used for producing my videos
Sony A6400: amzn.to/3hul53c
Sony e 24mm f1.8: amzn.to/2TqWNzk
Rode NT USB mic: amzn.to/3AdHcUp
Rode Wireless Go II mic: amzn.to/3xkCvGo
Rode Lavalier Go mic: amzn.to/3ygzzKY
Godox UL150 light: amzn.to/2VpVbXE
Godox QR-P70 softbox: amzn.to/3yQfGdF
MacBook Pro 14in (16GB / 1TB): bhpho.to/3HiafJL
Music: www.davidcuttermusic.com / @dcuttermusic
00:00 - intro
00:44 - size vs RF 14-35 and RF 15-35
02:30 - design and controls
03:43 - focusing for photos
04:06 - coverage vs RF 14-35 and RF 15-35
05:20 - optical quality vs RF 14-35 and RF 15-35
08:20 - night landscape quality
08:41 - astrophotography quality
09:36 - portrait quality
09:59 - closeup quality and bokeh
10:27 - diffraction sunspike quality
10:42 - video autofocus
11:10 - focus motor noise
13:06 - focus breathing
13:48 - vlogging tests
15:15 - vlogging on EOS R without IBIS
17:02 - lens correction and distortion
20:17 - verdict and sample images
As an Amazon Associate I earn from qualifying purchases - Věda a technologie
My in-depth review of Canon RF 16mm f2.8 lens! Vs 14-35mm vs 15-35mm
Canon RF 16mm f2.8 STM at B&H: bhpho.to/2XfeZxT // WEX UK: tidd.ly/3k9l8Es
Buy Gordon a coffee: www.paypal.me/cameralabs
Gordon's In Camera book: amzn.to/2n61PfI / Amazon uk: amzn.to/2mBqRVZ
Cameralabs merchandise: redbubble.com/people/cameralabs/shop
Gordon’s retro gear channel: czcams.com/users/dinobytes
Canon RF 16mm f2.8 sample images at www.cameralabs.com/canon-rf-16mm-f2-8-stm-review/
Equipment used for producing my videos
Sony A6400: amzn.to/3hul53c
Sony e 24mm f1.8: amzn.to/2TqWNzk
Rode NT USB mic: amzn.to/3AdHcUp
Rode Wireless Go II mic: amzn.to/3xkCvGo
Rode Lavalier Go mic: amzn.to/3ygzzKY
Godox UL150 light: amzn.to/2VpVbXE
Godox QR-P70 softbox: amzn.to/3yQfGdF
MacBook Pro 14in (16GB / 1TB): bhpho.to/3HiafJL
Music: www.davidcuttermusic.com / @dcuttermusic
00:00 - intro
00:44 - size vs RF 14-35 and RF 15-35
02:30 - design and controls
03:43 - focusing for photos
04:06 - coverage vs RF 14-35 and RF 15-35
05:20 - optical quality vs RF 14-35 and RF 15-35
08:20 - night landscape quality
08:41 - astrophotography quality
09:36 - portrait quality
09:59 - closeup quality and bokeh
10:27 - diffraction sunspike quality
10:42 - video autofocus
11:10 - focus motor noise
13:06 - focus breathing
13:48 - vlogging tests
15:15 - vlogging on EOS R without IBIS
17:02 - lens correction and distortion
20:17 - verdict and sample images
As an Amazon Associate I earn from qualifying purchases
Great review! will have a better watch later!
My first test with my 16mm RF (on an EOS R) was interesting but I've yet to do much with it...but at that price, why not!
The noise of the zoom was only audible when I turned up my volume and you were in the quiet room, after that it was negligible.... I have a 100mm RF f2.8 which is pretty epic, but the cheaper/and for me much lighter STM lenses I think these are also pretty decent, and when you include the difference in price I have to say some are my favourites....I use my 35mm RF all the time in the garden (shielding!)...well done Canon on bringing out these much more affordable, and alot easier to carry(!) lenses!
Thanks for doing the reviews! :D will share
Thanks for the astro bit! So far doesn't seem that bad of a lens for that area of photography, especially for the price.
This is by far the best review of this lens that I’ve seen. Including images from the 14 and 15 to 35 was extremely helpful. Haven’t seen anyone else do this and I have no doubt lots of people were curious about how they compared. Thank you for the amazing video. Just ordered the lens…..
Agreed, fantastic review Gordon!!!
You're welcome!
Whenever I need to know exactly what a camera and lens can do I look for Gordon's videos. It's almost criminal that he doesn't get more views. Thanks for another excellent video, Gordon!
@@derbagger22 thanks! I'm not sure why they get so few views either.
Fantastic all inclusive review. Thank you so much. Subscribed to your channel immediately. R6 + RF 16 lens in the bag. Hobby user. Regards
You're my go-to for photography info, Gordon. Always so professional and informative. Thank you and please keep it up!
I had ordered this when it was announced and still can't wait to get it. Your review confirmed most of what I assumed. This is going to be an awesome, small lens to carry with me for my non-professional video/photography work(YT & IG). I can see carrying this, the nifty 50 and my R5 with me for bike rides when I need a quick lightweight kit. Shrinking and cropping 45MP images down to smart phone size and I'm not to worried about sharpness!
thank you for including footage from a non-ibis model!! Glad to see us R owners haven't been totally forgotten haha
Really appreciated the EOS R demo as currently still rocking the R as a primary and M50 as my B cam. Looking to upgrade to an R6 as my primary at some point in the near future. Thanks for the video.
Gordon is, to my knowledge, the original CZcams “camera scientist.” Thank you very much Gordon for all your effort over the many years. Your in-depth, comprehensive, and precise explanations are much appreciated!
Thankyou! Yep, I was one of the first, I've been here since 2006!
Your reviews are incredibly thorough. Thank you, Gordon
The level of detail in this review is amazing. Thank you for the very detailed sample analysis comparing them with the more expensive zoom lenses. Great work !
Cheers!
Best photogear reviewer in youtube. Candid, concise, comprehensive.
Don’t be deceived by the seemingly simple presentation, I can see a lot of thought and effort being put in to the making of these videos.
Thanks! There WAS a lot of effort involved, this one took ages!
This is on my list of RF lenses to acquire. Looks like a reasonably good deal, though I'd have preferred less optical tradeoffs, even if that meant being a little more expensive.
Thank you for the great review! Especially for the autofocus noise and stabilization tests!
Hi Gordon, thanks for your review. If you want manual focus without going into the menu all the time you can use back button focus. In back button focus mode you can just turn the focus ring at any time and the lens will focus manually. Pressing the back button focus knob "AF on" you have AF. This should work with all EOS R models. I have tested it with the R and R6. The only drawback is you can't use the focus guide or focus peaking but 5x or 10x magnification works.
GREAT FIND, THANK YOU FOR SHARING
I don’t understand. Can I use square filters (nisi 100x100) with this lens?
Thanks Gordon, I especially appreciated the 14-35 and 15-35 shown as comparators. As an early adopter you can imagine the buyers remorse I'd have suffered if the 15-35 didn't produce better corner sharpness/contrast! All that said, given that most of the shots I've taken are at the widest end, I don't consider a prime is at all restrictive, (particularly one with such a small form factor ) and with a 2.8 aperture pretty useful for wide angle shots inside buildings. It seems that Canon are offering up something not usually seen ( a genuine range of choices for wide angle).
Great stuff Gordon! Always spot on! I have been using this badboy on my surfing kit, Aquatech Edge housing + EOS R5 + PD-85 dome and RF16mm) feels good and the quality is great! Keep your hard work going!
Gordon has some of the best reviews on the internet. Thank you!!
Thankyou!
Gordon! If your lens is set to AF in the menu and you select 'FOCUS' on the lens, you manually override the AF by half-pressing the shutter button. You do not need to go through the menu, or assign a special button. Just switch from 'CONTROL' to 'FOCUS' and half-press the shutter button. This makes the lens work like any other EF autofocus lens from EOS history.
Thanks!
Fantastic review. I wasn't aware just how much digital compensation could go on before I see the images.
Thanks for all the info in such an easy to watch video.
Very thorough as always Gordon. I bought the RF 14-35mm f4L lens specifically for making videos for CZcams as it was smaller and lighter than the 15-35mm but then Canon announced this little beauty for my EOS RP. Sold the 14-35mm and I’m very happy with the new 16mm. It does everything I want at a great price and small package for travelling.
Is there anything you miss from the 14-35? I do feel the 16 has somewhat stolen its thunder a bit...
@@cameralabs No, the 16mm is perfect for what I need, a wide angle in the 15-16mm range mainly for video/travel vlogs. I had no idea the 16mm was on the Canon lens roadmap and annoyingly you put your video out just after I bought the 14-35mm thinking it was my only option. The cost of that lens made me baby it and I don’t need a zoom. Paired with my RP and the 35mm & 50mm f1.8, it’s just great for me.
My last few videos for my channel have been shot using this lens. Video was my major reason. I have been using it with my R5 in crop mode to bring it to what 24mm ish? and love the look.
What an excellent review. It's made my mind up! Thanks😀
Thank you so much for the time you invested in this video, it is exactly what I was looking for.
You're very welcome!
Sold! just ordered a copy. Thanks for the excellent review
Another very good review Gordon. I've ordered one so thanks for this video.
You're welcome!
This was a really in depth and excellent review. Thank you very much. I have the EOS R6 and have found the RF lenses lighter and quick to focus. I am slowly replacing my EF lenses. For wide angle, I have the Tamron 15-30mm lens. It's fine, but two dings on it: First, it is HEAVY! Secondly, the canon version of this tamron lens cannot take any filters on the front of the lens. You have to put strips of a filter on the back of the lens. I can't imagine being at a waterfall for instance and taking off the lens to put in a tiny ND sheet on the back of the lens, then putting the lens back in the camera body. Plus, I've done real estate and architecture photography. I've read in other places that I could probably use the 16mm RF in tandem with the 24-240mm RF I have, only missing the 17 to 23 mm range. The price is amazing... for $299 US!
Thanks, this was the most comprehensive Lens review I have seen.
It's extremely important to my purchasing research.
You're very welcome, i try to be as thorough as possible! Hope you get to see some of my other reviews too...
THANK YOU.....I shot a few pictures this morning.....loving the lens so far
Fantastic coverage as always, Gordon.
Thanks, I don't think anyone else has gone into the same detail...
@@cameralabs certainly not! Always appreciated.
This video is absolutely exceptional, as your videos usually are; thank you!!
You're welcome! And thanks for watching more of my videos too!
By far the best reviews on CZcams!
Thankyou!
Now i know what I’m gifting myself for christmas. thank you Gordon!
Merry Christmas! Best order it soon though as it will sell out
Thanks for the great reivew, Gordon!
You're welcome!
Just bought one this week, can't wait to get it. Thanks for confirming my decision :D
Absolutely fantastic review as always Gordon.
Thankyou!
I always check your reviews before buying a lens. The only reliable channel for objective information on cameras and lenses. Thank you!
Thanks!
@@cameralabs There are hundreds of camera/lens review videos competing with each other, showing off with quick action shots, blaring rap music, pointless chitchat, bikini models ..... everything but useful, objective information. The thumbs-up vs thumbs-down ratio on your videos says it all.
Just bought it thanks to your videos. Thanks Gordon! It's a wild lens for sure.
Glad I could help!
Great job, I’m going to get one tomorrow at the Wales and west camera show in Newport, where I just bought my first canon yesterday. The lens might be cheap - but that’s for a lens- it’s also the price of the non discretionary replacement tyres for the back of the car, so even cheap can be a stretch In these times.
The best, down to earth, review of this lens that I have seen. Thank you.
You're very welcome!
The RF 14-35 f/4 has also significant vignetting (and profile correction) at 14mm, it is not optical perfect. But I like this, and I always used profiles on EF lenses too. If Canon can correct it and make the lenses a lot lighter, this is a good way for me. I saved a lot with using f/4 zooms (70-200 and 14-35) either, my bag is a lot lighter than with my old 5D3.
I hope for more affordable lenses though, like a 24mm (in this size).
Its great to have showcase lenses like an 28-70 f/2 of course... you can buy it, if you want - but for the most of us this would be just to heavy.
I also own the TS-E 17mm and the EF 135 f/2 - and I don't like the rumors of a 14mm tiltshift or an 135 1.4. Yeah yeah, set the amplifier to eleven, i know. These both lenses I will use with the EF adapter on my R5 till the end, because I dont think, canon would make them lighter/better than I already have..
And of course - thanks again Gordon for your reviews!
Thank you, Gordon.........you've made the decision to purchase this lens for my R6 much easier. (I just subscribed)
Wonderful, Gordon, as always. 👍🦘🇦🇺
Fantastic review. Way more than I ever needed to know, which is a good thing.
You're very welcome, thanks!
Another great review. I'm waiting on delivery of this one and I'm super excited. I've been shooting the 24mm pancake on my 250D since I broke a Tamron 28-75 for my 6D years ago. The other day I finally replaced that lens, put it on my 6D, packed it up and sent it back. I don't want to carry heavy cameras anymore. I'm so happy I found the tiny Full-Frame RP and these line of tiny RF lenses.
Thanks for watching several of my videos!
Thank you for the review, and the different ways I can use this lens.
You're welcome!
Great review as always
Thank you for these videos, Gordon. Very straight forward with the information I want to see. I have the RF 35 and 16. Just ordered my RF 85 f2 to replace my EF f1.8 that I recently dropped to the floor and messed up the AF/MF switch. After watching you review of the RF50 f/1.8, I have actually decided it would be worth the purchase, even though I already have the EF STM version. Even where you said that there was little or know difference, the images and video samples still seemed to favor the RF version. Going to try and buy you a coffee....
Cheers!
Def a great value proposition, ill be adding as a light weight option when i need to cut weight and for daylight shoots for sure.
Thank you! One of the best - if not the best - review
Thanks - excellent review. Ordered it right away.
Great Video, Thanks for covering the range at the low number (focal length range) I am very impressed with performance for astro and Vloging! the two uses i would use it for on my new R camera, thanks for sharing
I'm so impressed by this lens, especially comparing sharpness to the 14-35mm, which I consider to be quite excellent on the R5. If I was shooting more landscapes, like I used to I would definitely pick the 15-35mm, but now UWA is more of a rare use case for me and this lens seems perfect for that. Thanks for making such a detailed comparison with the L zooms, that was really helpful!
You're welcome!
the distortion looks very cool indeed, i'm really tempted to add this to my TS-E17 for fx shots.
I’ve ordered one and I’m pretty excited for it. Thanks for the review!
You're welcome!
Great review as always. Got the 16mm lens today. Not as sharp as the 35mm prime for those also considering, but acceptable given its price.
Thanks for as always a great review!
Another great review! Thanks for the comparisons to the 14-35 and 15-35. I have all three (yeah I like wide angle lenses)and the 16mm is great and is a no brainer. Time to buy you a coffee!
Cheers Rudy, much appreciated! What do you like about each of the lenses?
Excellent review! Thank you!
Your'e welcome!
I picked one up in the pre-order round. It is a fun lens and rounds out my kit nicely. For the money compared to other L series lens it truly is a no brainer. I use it on an R5 so for slightly tighter shots I have lots of room to crop in post. Very interesting how the Raw images are compared to the jpgs.
Good One Sir..I like it..beautiful clicks too
Wonderful lens for my Ra in astrophoto. I love it.
Thank you for your review, especially for the astrophoto-test! :-)
For astro the Irix 15mm is amazing. It's weather sealed and has a lock for infinity focus.
Looks like one for my R6. Thanks for review! Awaiting your review of the new RF 15-30 lens also.
I'm doing the new 24 first, but will then get onto the 15-30!
I do appreciate your real world reviews Gordon. I’ve seen a few reviews from you tubers who have dismissed this lens because of the distortions, but like you say in the video, it’s the end image that matters and it seems for the money this is a very good lens. I have an eos R and I think I will certainly consider this lens.
Please tell me your doing a review of the new RF 100-400 ( the cheap one ) as there doesn’t seem to be that many good reviews on you tube at moment and that is a lens I’m very interested in.
Cheers and thanks for all your hard work, it is very much appreciated.
Good news, I'm working on the 100-400 as we speak!
@@cameralabs Thank you Gordon, I’m looking forward to viewing that video.
Used it for landscapes and some vlogging allready in my latest video. Actually really like it. And sooo light.
Glad you like it!
Another great review Gordon. Indeed, given its portability, image quality and price, this looks like a must have for those interested in wide-angled photography.
I routinely use RF 14-35mm f4 L, RF 70-200mm f4 L, RF 100mm f2.8 L, RF 100-500mm L, and this tiny little RF 16mm f2.8 STM wonder on my R5.
Your test routines and final conclusions are the most relevant and accurate I've seen so far.
Keep up the good work.
Thanks! Hope you've also seen my 14-35 review!
@@cameralabs Sure, and that review is completely in line with my experience too. It's quite uncommon to find a reviewer that you agree with almost everything.
I've been waiting for your review!
And here it is for you! Hope you find it useful!
I have been playing with my RF16mm lens for a week - landscape photography et al, "proper" video and vlogging. I am very pleased with it. I shoot RAW images which currently I edit using Canon's DPP4 software which of course, possesses the lens profile.
You definitely need that profile!
Are there differences between using DPP4 and affinity/Lightroom in relation to native features?
I was pretty excited to get my hands on this, and have already put my order in for one. I am looking forward to using it!
I think the stabilisation on the R5 looked great, no wobble on the edges to be seen. Canon have done well.
Thanks for your contributions Ben!
From start I can see this video is a fantastic one. Awesome
Hi Gordon, thanks for the review.
Maybe you could give us a video on how to configurate the lenes corrections in the raw mode?
3:07 The R7 and R10 are exceptions to this as there is a physical AF/MF focus type selection switch on the camera body which is very convenient vs. having to navigate through the menu system to make the same change.
thanks for the review. It's very interesting and informative. One small thing though about testing the noise level of the focusing motor, it would be more helpful if you did the test while wearing a lavalier or having some other type of audio set up. Real world situation would almost never use on camera mic so it's difficult to gauge how big an issue it is just using the on camera mic. I know it's a pain to set that kind of thing up, but that would make the test more useful. but overall great video.
You won't hear it with a lav mic if you're more than 30-40cm away.
Great review. I bought this lens becuase of you to replace my Tokina 16-28 2.8. Use it for real estate.
Your reviews are thorough, detailed and approach. Fantastic work! Can we expect a review on the RF100-400mm F5.6-8 IS USM in the coming days or weeks? Your sneak peek definitely made me want to know how it held up against its L-series big brothers (EF and RF versions).
I'm working on it right now!
Great review. I want one!
Lightroom updated to now include the RF 16mm f2.8 lens correction profile
Hurrah!
I bought this lens on pre order the day it was announced. It is a perfect fit for my EOS RP and hasn't let me down ever. Like you said, a no brainer. Now if they could just make 28mm f2.8 to match. I would have 3 lenses (including the 50mm f1.8) in a tiny light weight full frame kit. Add the RF100-400 or maybe the 70-200f4 to get the telephoto reach. I would be very happy with that!
Yes, a 28 would be nice, but the 35 is good!
lol you just detailed my exact kit. The 70-200 f4 was the best thing ever for my wedding/event shooting. The 16 is in the mail, looking forward to using it for landscape up in the Arctic. Had the 50 f1.8 since the summer and it's my go-to for portraits and general shooting. Don't see myself needing anything more, until I save for a 500 f4 for wildlife.
@@omarcaneomedia I recently picked up the RF 35mm f1.8 , also a no brainier. But the 16 and the 50 are so good together with a 70-200 that you should have all 4
great review, picked one up today to pair with my 50 1.8/samyang 84 1.4.
Carting around the 14mm 2.8 with its bulbous front end just wasnt suitable for a small messenger bag - this is cheap/small/light enough to just chuck in the bag
Exactly!
That focusing motor is pretty loud, but that is not unique among Canon lenses (even L series in my experience). However, I use a lav mic and wireless transmitter so it's no issue for me.
I think the heavy distortion correction is what's causing the difference being larger between 16-15mm than 15-14mm... Normally you'd expect the latter to be a bigger difference. Heavy corrections always comes at the cost of a bit of croppage... So i wonder if this isnt actually more true to a 17mm lens after corrections
Thanks for this review 🙏🏻
You're welcome!
Another great review, thanks! Have you had a chance to play around with peripheral illumination correction while shooting video in one of the C-Log variants? Canon warns against excessive noise in the corners and suggests disabling peripheral illumination correction, but I haven't had a chance to test it.
Good question and sadly no I haven't.
Great review 👌
Thanks!
Great review!
Your method to test corner sharpness is by far superior to those using the test charts!
I will not worry about the AF noise, so I can't wait getting this lens on my EOS R body.
This lens is a nice little beast.
not bad at all for this size. Thanks for review
Man, if Gordon Laing isn't on Canon's R&D payroll he certainly should be. This review, as always, goes way above and beyond. This should be required viewing for those looking seriously at the 16mm.
Thankyou! They do humour me by asking for feedback, and this time, the MF / AF switch complaint was actually addressed in the new R7 and R10 bodies!
This is the best review for the 16mm ive seen to date! Everyone else makes it seem like the worst thing ever & completely unusable 😂 Thanks for this. I dont think the noise from the focusing is an issue. Well done!
Thanks! It's easy to point out what's wrong with something, but important to then see if it will actually be an issue for you personally. This lens definitely has its faults, but I still think it's brilliant!
Great review! As always.
I would love one of these. For what I do though, I'm leaning more toward the 85mm. I use the 50 and 35 constantly. These RF primes have been absolutely solid.
The 85 is also really good - have you seen my review?
@@cameralabs me yes! One reason why I bought it! Prime lenses are way better than zoom.
@@cameralabs I haven't.... I'm off to check it :)
@@Bassbarbie great! I've reviewed almost all the Rf lenses.
Great review, Gordon.
Thanks!
A great video! Thank you!
You're welcome!
another fab review and another item added to my list of things to buy lol
thank you for thisss
Great work as usual
Thanks!
Just ordered this lens. Some video reviewers were critical of heavy distortion as Lightroom or camera profiles, not sure which, weren't up-to-date at the time. I'm guessing that this has been fixed by Aug 2023?
I'm told that it'll be a good lens for streetscapes. I'm travelling from Australia to the UK in September and so I've bought it used off of Ebay. I'm also taking the RF 24-105L f4, so whichever is better for landscapes, streetscapes and so on it'll mean an easy set of camera (R6) and lenses to carry around with me.
Thanks again for the reviews Gordon. It's appreciated.
Yes it should be fully supported now
5:03, that actually shows how the 14-35 f4 is not a real 14mm! Seen that in Dustin Abbot review also. This lens is really a no brainer in Canon RF system specially considering how overpriced the others like that 14-35 f4 zoom lens are. And you will get an extra 14mm fisheye lens for free too! It's biggest weak point is that noisy focus motor which is completely abandoned by even third party manufacturers in mirrorless system at this time. Thanks for the great review!
I am not a Canon user but I am very jealous of this lens. A compact lightweight just in case UWA that is, good enough is a great idea.
exactly
For anyone worried you are "losing" MM because of the crop you are not. The warped RAW image is closer to about 14mm so that the corrected image is at 16mm, 06:09 shows an example of this. I hope I end up being wrong but I don't think we will see a Camera RAW/Lightroom profile for this for some time, it took Adobe 1 year to put in a profile for the RF 50mm you mentioned early in the video.
Hmmm, I didn't realise it took so long for them to do a profile for the 50.
@@cameralabs Yea they JUST added it in the major October update. Almost 1 year after release.
Strong review, thank you!
Thankyou, I feel I covered everything!
Hi Gordon :-)
Im dissapointed with the quality of the 14-35 f4 for that price. While for "its price" the 16mm seems fairly OK (especially because im a R6 user and dont own a R5 that can peep deep into its corner).
In hinsight yes i wish i have gotten an R5 but i could afford a lense and extras for that price difference. As for the zoom, im still using my 16-35 f4 adapted as due to its weight and size, its not much different in hand than it was without the adaptor. (E.g. the 70-200 f2.8 is ii gets super front heavy adapted, thus i got the new one, its also much shorter and lighter, which is great for hiking).
As on your questions, for Astro id still use my Samyang EF 14mm f2.8 or my sigma EF 20mm f1.4 (either no coma and a bit darker, or a bit of coma but much brighter) - yet for a landscape or similar photography, i think its a really nice compact and fun option. Thus yes i think especially with lenses that arent 100% perfect in sharpness its vitally important to test its performance in its relative application field to geet a reference of how much that impact actually is. Id wager that using this lense for Street (illegal grey zone in switzerland) or similar, you wouldnt notice the sharpness drop off at all.
Set the AF-ON button work as AF-OFF and then pressing that you can use manual focusing without going through menus.
Yes, but that's not practical for presetting a manual distance under magnification for astro work.