Why would anyone want a fixed 300mm lens with a small aperture?

[shortylickens]

http://www.amazon.com/Samyang-SY300M...dp/B00DRC9JBE/

What purpose does it serve?

 

[Silenus]

For small size, weight, and CHEAP price for the given focal length, that's basically it. Wide aperture costs you in size, weight, and money and it increases rapidly with each stop.

 

[OctaneZ]

What Silenus said, it is a mirror rather than a "traditional" lens, it buys you a longer focal length at a small small fraction of the price and weight of a "normal" lens.

 

[blastingcap]

Mirror lenses = funky bokeh

 

[Gooberlx2]

Mirror lenses = funky bokeh

Indeed. Which, depending on the image of course, can look kinda rad.

 

[Throckmorton]

Mirror lenses are sharper right?

 

[Gooberlx2]

Not according to photozone. I think their example pics look pretty damn sharp, but they give the caveat that they were taken in ideal conditions.

http://www.photozone.de/mirror-lenses

 

[shortylickens]

For small size, weight, and CHEAP price for the given focal length, that's basically it. Wide aperture costs you in size, weight, and money and it increases rapidly with each stop.

I guess its kinda OK for saving money, but it seems to me you trade off a LOT of versatility.
And I'm not sure but I think I can get low end zoom lenses for roughly the same price, yes?

 

[OctaneZ]

And I'm not sure but I think I can get low end zoom lenses for roughly the same price, yes?

I don't know what system you are on, and it's won't get you to 300mm, but reviews of the Canon 55-250 STM point to it being a great lens.

 

[Anteaus]

This Rokion mirror lens features a fast F6.3 aperture for much brighter images.

You know, advertising like that would be enough to dissuade me from a lens like this. There is nothing fast about f/6.3 but fast enough for daylight shooting I guess. Without seeing the lens in action, the only thing I can see going in this lenses' favor is the price.

 

[Paladin3]

I used to carry a Canon FD 300/4 in my bag because always carrying a 300/2.8 was too much. Back then the Nikon shooters carried the Nikon 300/4.5 and I thought losing the extra half stop made it too slow to be useful. F6.3 would be really bad.

Anyway, real pros uses lenses like this $99 Rokinon 500mm f/8.0:

 

[yhelothar]

Mirror lenses are sharper right?

I'm not sure about sharpness, but mirror lenses doesn't suffer from chromatic and spherical aberrations that normal lenses do(unless you pay an exorbitant amount of money for the ones with ED lens).

 

[blastingcap]

I used to carry a Canon FD 300/4 in my bag because always carrying a 300/2.8 was too much. Back then the Nikon shooters carried the Nikon 300/4.5 and I thought losing the extra half stop made it too slow to be useful. F6.3 would be really bad.

Anyway, real pros uses lenses like this $99 Rokinon 500mm f/8.0:

f/4 to f/4.5 is not half stop, it's hardly any difference, and the actual transmission of light were definitely different so it was probably more like t/5 vs. t/5.x or something like that.

 

[Red Squirrel]

For around that price you can also get this:

http://www.amazon.com/Rokinon-650Z-B...rokinon+1300mm

Recently bought this lens and it's pretty good, though I did not get much chance to try it out yet. The F stop is kinda high but it's to be expected in this price range.

This lens is far from portable though. Not something you take with you on a jog through the nature trail.

 

[ElFenix]

similar tokina for less money:

http://www.bhphotovideo.com/c/produc...l/prm/alsVwDtl

also has pictures of it on an olympus pen; these things are tiny. that's the main benefit.