All camera lenses are pretty much the same right
wrong in this video we're going to be talking about a camera lens that throws out the rulebook
and almost gets away with it intrigued keep watching but first here's a history lesson
Mirror lenses or catadioptric lenses to give them their official title can trace their design
back over 200 years to early telescope development fast forward to the 1970s and 80s and these lenses
were redesigned to fit the growing 35 mil slr market their simple construction
meant they could be produced at an affordable price and approved extremely popular.
So how do mirror lenses work then well it's quite simple really
here's a mirror lens what happens is we've got the front element there
light passes through like it does in a conventional lens it comes to the back
of the mirror lens and there we have the concave mirror it fires it then at an angle back to
the front element where you've got this central mounted mirror and then light passes back through
to the through the rear element and onto your image sensor in your camera quite simple really.
So with all that science and astronomy background these mirror lenses sound too good to be true yes
well you'd be right and the first thing I should mention is that no professional photographer
I know uses a mirror lens in their commercial work we'll get to why that is during the video but
if you're a hobby photographer on a tight budget should you consider buying a mirror lens
on paper it's a short lightweight if slightly bulky 500mm telephoto lens and which would cost
you new for around about £120 that does sound like a bargain but there are a few caveats.
The first thing to consider is that this camera lens is completely manual there is no autofocus
or image stabilization in this lens at all so if you like to just mount a lens to your camera
stick it in auto go and take some very nice pictures then this is not the lens for you
another point to consider is that this lens is a t-mount and you will need an adapter like this
to screw onto the back of the lens. Now usually when you buy a lens from the likes of Amazon or
one of the photographic stores it probably will come with a suitable t-mount for your camera. If
you're buying second hand and you don't have the t-mount in the listing or wherever you've picked
it up from don't worry these are really cheap and you can buy them online from the likes of eBay for
about four or five pounds also often included with the lens if you buy new it's something like this
which is a two times teleconverter so that makes your 500 mm lens into a thousand millimetre lens
but beware all I found out with this was it actually magnified not just the image
but also the issues you have with the lens the next thing to consider is the fact that this
is a fixed aperture lens you can choose from 6.3, 6.3 oh yes you guessed it 6.3 it's fixed aperture
nothing you can do about that the only way around it would be to raise either your ISO
or alter your shutter speed to compensate. Third point to consider with this lens is the bokeh.
Now while some lenses produce circular or sometimes an oval bokeh,
the mirror lens produces doughnuts and unlike Homer Simpson not everyone is keen
on donuts. The donut bokeh is caused by this central mounted mirror
and whilst if you have a chip or a scratch on the front element of your conventional lens and you'll
find that it's very unlikely that you can actually see that in the final image that's because light
will bend around those imperfections there are limitations about what light can do and this
is it. Some people do like the donut shaped bokeh and it certainly has its own place in photography
sometimes it's quite severe and quite distracting other times it kind of adds to the image.
Next issue that you might find with the mirror lens is sometimes the images lack contrast
they may appear a little bit washed out and that was obviously a disaster
back in the day when you were shooting colour film
but with modern digital cameras you can always address that in post and it's not such an issue.
One issue you might encounter with the mirror lens is just the basic usability of it because of that
fixed aperture bright light is a necessity and that will mean that you will as I've said earlier
have to play about with either raising your ISO or raising or lowering the shutter speed.
Another issue to consider despite the fact that this lens barrel is quite large and the focus ring
isn't too bad it is really really difficult to get a sharp shot and that's because
the depth of field on these mirror lenses is razor thin.
That said if you were only ever going to be using your images on social media
or producing only small prints then I would not let that put you off buying this lens
because you'd be able to sharpen up those images when you reduce the size of them.
So I think that's pretty much the negative issues with this lens out of the way
so are there any positives well one positive is that this lens is designed
as a full frame lens so if you are for example an owner of an aps-c camera like my Nikon d3300
then due to the crop factor this 500mm lens is now an 800mm lens if however you are shooting a
micro four thirds then this 500mm lens now becomes a 1000 millimetre lens. The trump
card for this lens as far as I'm concerned is for taking photographs of the moon why
because your focus is going to be set to infinity therefore the bokeh is not going to be an issue
in addition if you'd like to shoot photographs of non-moving wildlife so birds sat in trees
and things like that then you'll find this is quite a good lens to get you much closer
to the subject than you would be able to do with a kit lens.
Yes it's true national geographic is not going to be knocking at your door
for your photographs but if you're just taking photographs for your own enjoyment
then the images are okay that said it is quite a fun lens to use
the range is pretty amazing and you can grab details that no kit lens could ever reach.
So to sum it up first we'll go through the pros and cons
First we'll go through the pros what are they well it's a 500 millimetre lens or more
depending on what camera you fit in the two costing you about 120 pounds new or even less
if you buy one second hand. Secondly it's quite fun to use, different and sometimes challenging,
but still quite a fun lens to use, you'll enjoy using it even if it tests you at times.
The third thing is it's a compact size for a 500 millimetre lens so should fit into your camera
bag no bother at all, and then oh yes that donut bokeh if you like that sort of thing.
So the negative points what are the cons? Well that fixed aperture makes it more
difficult to use than it would have if it had an aperture ring, images can sometimes be soft
but as we say if you are reducing the size of the images you can sharpen them up then anyway.
It's manual everything that's another thing there's no assistance whatsoever,
another point is the shallow depth of field now that's going to be a challenge to use but
sometimes it can give you a different feel to your photography, and lastly the donut bokeh if you
don't like that sort of thing! So ultimately would I recommend a mirror lens? Well if you like your
photography to be easy then perhaps this is not the lens for you but if you're on a tight
budget and there's no other way of you getting a 500mm lens then perhaps you should consider one.
The images within this video should show you the type of results you're going to get and
also I've listed all of the pros and cons of the lens so you can make up your own mind.
Ultimately though it's whether you're prepared to put up with the entire manual setup of the lens
and of course that donut bokeh so I hope you found this video informative and has helped you make a
decision one way or another if you have enjoyed it please consider subscribing to the channel
and please do give this video a thumbs up it really does help a lot
thanks for watching and we'll see you again next time bye for now