Long time viewers of this channel will know that I love fisheye lenses for astrophotography. I
find the perspective of taking in so much sky in one photo really fun and rewarding. And I
did a shootout of fisheye lenses a couple years ago and when it came to the Sigma lenses in that
shootout I found the Sigma 8 mm circular fisheye was pretty good but a little slow at f3.5 wide
open and then I found sigma's other offering at that time the diagonal fisheye the 15 mm f2.8 was
disappointing for Astro it was a little faster than the circular fisheye but it had a lot of
distortion on the stars even way stopped down to something like f5.6. Well fast forward to a
couple of weeks ago and Sigma America sent me an email saying we have this new fisheye lens could
I review it and I was prepared to actually say no because I have a lot going on right now with the
solar eclipse coming up in under 2 months uh but then I looked at the details in the email
and I saw number one one this is a fisheye lens in their art series which is reserved for their
very best lenses optically and then number two this is an f1.4 fisheye and that's just you know
unheard of it's literally the first f1.4 full frame diagonal fisheye lens ever uh and in my
fisheye shootout video a couple years ago to give you some perspective the fastest fullframe fisheye
lenses I had available and tried were f2.8 a full two stops slower than this lens and so when I saw
these details I thought you know I got to try this lens I I'll move some things around make this work
and I also knew from those details that this lens was going to be really expensive and a few days
later they emailed the price which is $2,000 us and I get it that is really expensive for
a specialty uh lens like a fisheye but this is no ordinary fisheye sigma's really created something
here that is one OFA kind uh because typically with fisheye lenses I've always thought of them as
you know they're fun you you know you you get that kind of wild perspective but they're not the kind
of lens that you would hold to a high standard in terms of technical performance they're not
like sharp lenses I wouldn't consider them high resolution lenses that you would really be able
to resolve a lot of details or or nice star Pro files from um and they're typically not very fast
either so maybe not the best for astrophotography. My favorites from that shootout that I did were
actually some of the slowest of the bunch f3.5 or even F4 wide open in terms of the Canon so to
have a fisheye come out that is well corrected and sharp across the field at f1.4 using a 61
megapixel sensor is just mindboggling to me as a lens nerd and a lens collector I'm very impressed
at what they've achieved here but all that said in terms of practical considerations this is still a
specialty lens with a high price point fisheye is probably not in most photographers bags because
it's not your typical way of seeing the world it's it's a little bit weird right uh you get that
fisheye Distortion that a lot of photographers maybe don't like but before I go any further with
get more into the details and the Imaging tests that I've done with this lens let me share uh the
disclosure since this is a review Sigma America sent me the new lens the 15 mm f1.4 DG DN diagonal
fisheye as well as a sigma fp-L camera and a sigma 14mm f1.4 dg dn Sigma 14 was at my request cuz I
was interested in comparing it to the fisheye here and this was all sent to me 11 days ago
which allowed me to quickly get out and do some tests and put out this review to coincide with
the announcement of this new lens today I'm not paid by Sigma they have no input into what I say
in this video and after the video is released I'll be returning all the gear to them so on with the
review let's talk a little bit about the physical characteristics here of this lens like the 14 mm
f1.4 dg dn that Sigma released 8 months ago this is an incredibly heavy lens actually another 200
g heavier than the 14 mm the 14 mm is 1,170 G or 22 lb the 15 mm fisheye is 1,360 G which is 3 lb
and like uh that other lens the 14 mm to support all of that weight comes with this tripod socket
which is a nice rotatable ring with an Arca Swiss compatible foot for mounting on your tripod and
this ring allows the lens to easily rotate to any orientation including vertical horizontal
but anything in between this lens is in sigma's DG DN art line so that means it's for mirrorless
cameras and mirrorless full-frame cameras at the moment just Sony e-mount and L Mount are available
I testing the L Mount version of the lens um I'm testing it with sigma's Flagship camera the fp-L
with its 61 megapixel sensor for Astro and Camera nerds out there this is the famed Sony IMX 455
sensor that is also in the Sony A7R series the newer ones and several full-frame Astro cameras
like the QHY600 the ZWO ASI 6200 it's a very good sensor for testing Optics it's the same
sensor I use for testing telescope Optics these days uh it has a pixel pitch under four microns
so it's not going to hide any faults you know any Optical aberration that are there are going
to be apparent other than that this lens is very consistent uh in terms of features with the 14mm
f1.4 that I reviewed a while ago it has focus by wire meaning you can't use this on an astronomy
camera it needs electronic Focus uh the electronic Focus can lock with a switch which is cool it also
has the lip up here to prevent the do heater band from slipping into to the field of view that's of
course very appreciated on a fisheye lens cuz I do actually remember struggling with that a bit
when I did the fisheye lens uh shootout it's very easy to have that do heater band uh just
come up a little bit too far and then you get it in your shot again like the 14mm Sigma is
definitely designing and marketing this lens for astrophotography which is really cool that they're
paying attention to our Market which I'm sure is not a huge Market compared to like sports Wildlife
landscape some of the other domains that Sigma is targeting so I think it's really cool that Sigma
is making lenses for astrophotographers so let's take a look at the images that I've taken with
it now and we'll compare them to uh shots with the 14mm f1.4 which again is a rectilinear Ultra
wide that I've reviewed previously and for me the reason I'm interested in comparing it is that was
the champ you know that's the champion when it comes to technical performance on an ultra wide
angle so I think it's going to be interesting to compare this uh new fisheye lens from from
Sigma to that one okay let's jump in here all these images you're going to see in these tests
were taken on February 13th from 7: to 8:00 p.m. from my uh backyard Observatory I was considering
going somewhere more exotic but uh I just wanted to get these uh tests in while I had the lens uh
because it was a pretty short review period I put the lenses on my skywatcher Mount which is on a
pier in the observatory as mentioned I was using the sigma fp-L camera at ISO 1600 all of these uh
test images are going to be straight from camera so that means you know in processing you would
change the contrast and colors and things like that but these are fairly uh flat images that
haven't been processed much because uh it's easier to see sort of what we're looking at uh if you
don't process the images at the very end I'll show sort of what it would look like if I if I
did a light processing on the on the picture the moon was was up but it was pretty low in the sky
and out of frame and it was only 20% illuminated so it was still a fairly dark sky I have about a
bort three sky here and what you're seeing here uh emanating up and to the right a little bit
in both pictures is the winter Milky Way and for people not familiar the winter Milky Way in the
northern hemisphere is not nearly as prominent as the summer Milky Way where we see the core
where we're looking into the core of the Galaxy in in this comparison which is the full frames
from each uh camera of course the first thing you might notice is that they're fairly similar but
there are some key differences that jump out at me right away one is that the stars look a lot more
prominent in the upper half of the photo in the Sigma 14 the rectilinear lens than they do in the
fisheye lens and this will bear out again in the in the crops uh especially looking at the corners
because what's going on here is the rectal linear image has to correct these Corners which actually
uh makes the Stars a bit wonkier right um it it's good for foreground things because it makes the
lines more straight and look more natural how we would see them um you can see we have pretty uh
extreme fisheye Distortion in straight lines in the lower half of the image here but in terms of
rendering a star field which you can sort of think of as a dome above us the fisheye image
actually gives you tighter Stars across the whole full-frame image well with the rectilinear image
because it's having to correct those Corners the stars get a bit bigger and more pronounced in uh
the extreme corners of the image now it's still doing a great job for an ultra white angle don't
get me wrong but I'm just uh sort of pointing out a key difference here between a fisheye
and a rectal linear length another thing you may notice and I've zoomed in to show this a little
bit better is that I'm centered on Betelgeuse here but sort of my goal with this image was to show
off this cool asterism called the winter hexagon and so it's in each image but if I put some lines
to show how those Stars connect the winter hexagon goes from Sirius at the bottom to Capella at the
top you can see that it does sort of change the shape a little bit of the winter hexagon it gets a
little bit more stretched out in the rectal linear image and then also uh it's a little bit more
zoomed in with the rectal linear image like we're we're getting a wider field of view here there's
more headroom above the winter hexagon than there is here remember that this is a 180° field from
corner to corner and this one's 114° the other thing I found really interesting um in looking
at these images was if you look at this cluster right here this is I believe Melotte 20 it's the
it's that that big open cluster at the center of Perseus in this image it's right here in the
frame and it looks nice and tight in this image it gets out here and look how much it's expanded due
to that how it's correcting the corners um it's it's pretty amazing I think if if you I should
have mentioned this earlier but you can download all of these slides and images because I know that
it's going to be hard in a YouTube video to really appreciate this I can't emphasize enough how weird
this this image is to have perfect stars but have the fisheye effect of like how we actually see the
night sky um as a dome you know where where it's curved um but but then then to have perfect Stars
across the field it's a really trippy image and and it's and it really rewards zooming in
and just sort of looking at it it's almost like a it's almost like a survey image like a mosaic and
how perfect the stars are across the field okay now I'm just going to run through my standard
comparison whenever I review lenses I start with vignetting here vignetting is how much you have
shadowing in the corners uh due to light fall off how you know how well it's Illuminating the field
and of course this is full frame so this and usually vignetting improves as you stop down
the lens so this is at f1.4 so this is the worst it is going to get and I would say it's perfectly
acceptable on both lens um but maybe a little bit more strong wrong in the uh Sigma 14 but almost
the same it looks like the diagonal fisheye has taken the lead in terms of uh how flat it is I can
still see a bit of uh vignetting at the whole top of the frame up here and on this one it's it's so
minimal it's barely gone it's almost gone and then at f2.8 this one looks perfectly flat to me so I
think it at f2.8 the the fisheye is now just flat field like I don't see any issue with vignetting
there this one I still see a little bit in the corners at the top okay and then at F4 they both
look flat so I I don't really see any vignetting in either image in F4 okay here's the center crops
at f1.4 and this was interesting to me too just how similar the star fields are in the center
uh between the diagonal fisheye and the uh rectal linear image I mean I I guess this all makes sense
this is something I've never really thought about that in the center of a fisheye image and a rectal
linear image if you're talking about the same uh or almost the same focal length they're going to
look incredibly similar the stars are going to be spaced about the same but then it's really
just when you get F when you get away from Center that they change so dramatically I'd say the the
sigma for is maybe just slightly tighter slightly better color um like if you look at Betelgeuse
here it looks a little bit more saturated than on the 14 than it does on the fisheye um and
then this star here I can't remember the name of it um it's the other shoulder of Orion again it
just looks slightly uh tighter on the Sigma 14 okay and then here at f2 they look remarkably
similar and that's just what I found with the rest of my images f2.8 F4 these all just look perfectly
matched I don't if you if you ask me which one is which I would have no idea they're so close uh uh
to each other color uh sharpness Clarity you know I I don't I don't really see a huge difference uh
between these lenses at center now it was a completely different story in the corners as
I sort of alluded to when we were looking at the full frames um because the rectal linear image the
the Sigma 14 has to correct the corners to get rid of all you know the barrel Distortion and
give you straight lines the star field is going to be quite a bit wonkier compared to the center
while with the fisheye the corners of this lens look about as good as the center now not quite
I mean if I zoom in you can see there is a little bit of uh Distortion there but that is so minimal
compared to this one right this is at f1.4 look at that we have little uh little rabbits if you
zoom way in the little bunny ears well this one they're just slightly elongated but uh zoomed out
this is already at 200% Zoom it just looks like the stars are much bigger and spaced further apart
and a little bit blurry with the 14 mm and with the 15 mm fisheye they just look perfect I mean
you really have to zoom in to see that there's anything weird about the corner Stars so that's
amazing I don't I don't know how to really Express how interesting this lens is to me now in terms
of what you could do with that artistically I'm not sure yet but it it's it's technically just
a really interesting lens okay and then here's F2 it's you know it's basically you get slightly
better correction with both but really it's the same story they they look about the same and it
just sort of continues you know slightly better correction at f2.8 but still a huge difference
between the two and then at F4 I do think that you know the Sigma 14 Ultra wide angle it's starting
to give you sort of round stars but they're still quite a bit bigger and spaced further apart uh
with the sigma 15 let's zoom in and take a look at them yeah they're they're nearly perfectly round
even this is probably zoomed in at like 800% now and they look just great um on here if we look at
the Sigma 14 we've gotten rid of the little rabbit ears they're still a little bit elongated I'd
actually say the in terms of um star profile star shape these are not too different to the the big
difference here is just they look a lot tighter uh with this one just to due to how the fisheye
effect is rendering the star field versus the rectilinear lens okay and then last thing I want
to show you here in this video uh is just this is an example of an unprocessed image straight from
camera this I believe I shot at f2.8 about uh 60 seconds at ISO 1600 and then here's how I would
do a nice processing on it now my processing might not be exactly to your taste but just to show you
again here's straight from camera and here's with processing and all I really did was I brought out
the winter hexagon by making those Stars slightly accentuated and brought out uh some of the the
dark nebula features in the winter Milky Way and some of the other nebula features now this is a
stock camera it's not modified for H Alpha so it it's not going to bring out something like
Barnard's Loop and a single one minute picture but we can see the Rosette here right in the
middle of the winter Milky Way uh and we can see the California nebula up here and there's
the Pleiades the Hyades so to sum up it's it's a super interesting lens if you're really into this
look I could definitely see getting it I'm I'm considering saving up for one for me the whole
reason to have the uh Sigma fp is really for these new mirrorless lenses that I find so exciting and
this one is super exciting I mean to have this kind of star field with a with a fisheye lens who
knew that was even possible so uh hope you enjoyed this one looking at this new lens from Sigma
uh if you have any questions leave them in the comments this has been Nico Carver, clear skies!