nikon 28mm f1.8g or 20mm f1.8g or 20mm f2.8d?

[Charliedelta]

I am looking for a lens to shoot underwater in a water housing for my Nikon d7100. I need something in the 20 to 30mm, and I came down to the Nikon AF-S NIKKOR 28mm f/1.8G Lens
and the Nikon AF-S NIKKOR 20mm f/1.8G ED.


What do you think about the Nikon AF NIKKOR 20mm f/2.8D Lens ?

Which one would be sharper? Alternativerly I have a Tokina 12-28mm f/4, which I could use at either 20mm or 28mm and not buy the prime. But sharpeness is my priority, so I am wondering, would these primes give much sharper images than the Tokina?

 

[Charliedelta]

I meant that I would use them underwater and above the water like in the waves

 

[fjrabon]

I'd go with the sigma 18-35 f/1.8. It's essentially all of those lenses wrapped up into one constant f/1.8 aperture. Razor sharp. Great build quality and ground breaking focus calibration system.

 

[unpopular]

In my opinion, 28mm is a pretty useless length. I've never found much need for it, either in 35mm or APS-C.

A 35mm length is a better choice on either format, and 20mm I think is good, provided that you have a decent standard lens (i.e. 50mm or 35mm)

 

[Derrel]

Seems like flat or domed port has some impact on the efective angle of view of the lens...

Advanced Underwater Photography Techniques for Digital Photographers - Larry Gates - Google Books

 

[fjrabon]

In my opinion, 28mm is a pretty useless length. I've never found much need for it, either in 35mm or APS-C.

A 35mm length is a better choice on either format, and 20mm I think is good, provided that you have a decent standard lens (i.e. 50mm or 35mm)

I like 28mm a lot on a full frame. Its a great environmental length (it's considered one of the primary street lengths, it's what Ricoh and Nikon both chose for their aps-c fixed lens cameras). On a crop frame it's 42mm equivalent, which a lot of people like (I recall derrel saying he used it a lot in a thread the other day). It's kind of like a loose 50mm. It basically allows you to straighten and still have 50mm for street/photojournalism.

 

[unpopular]

I don't know. It seems like a neither-nor lens to me. Never had much use for it. I especially don't care for 28 on APS-C. The lens still felt "wide" to me, but didn't have the FOV. DOF-wise, it felt like shooting a 50 at f/5.6 all the time.

My C/Y Distagon 28/2.8 was super sharp though, a lot sharper than the Planar 50, but didn't seem to render color as nicely, didn't have that Zeiss quality to it as much.

 

[Dave442]

Both these new Nikon lenses are sharp. The 20mm focuses closer.
I suggest going with the Tokina as you have that. But, a new lens is always fun to use so if it was in you plan anyway then pick up the 20mm. Then you won't be wondering if you should have after the trip.