[gump]

I know Ansel Adams sent the Pentax 15 mm from heaven, and it is on my list, but after reading a lot of reviews I would like to confirm a couple of basic assumptions.

Everyone seems to agree that the Rokinon and Samyang lenses, especially the 14 mm and 16 mm, are identical, any arguments?

The 14 mm, although designed for FF can be used on the K-70. Aside from things like filter-no filter or the the usual standard review categories, are there any "problems" that reviews overlooked in using the FF lens on an APS-C?

Excluding fisheyes, is there a consensus on a max angle of a wide angle beyond which distortion and such get to be too much of a pain?

[Sandy Hancock]

Rokinon and Samyang are most definitely the same lenses. I think they also are sold under the Bower brand.

Any full frame lens can be used on an APS-C camera. Without exception.

A properly rectilinear lens will be rectilinear on full frame or crop. Composing really wide lenses gets quite challenging whether they are rectilinear or not.

[pepperberry farm]

DA14/2.8 would be my choice... and it's great for other types of shooting, too...

[jatrax]

Rokinon and Samyang lenses

Same company, different brands, identical lenses.

The 14 mm, although designed for FF can be used on the K-70. Aside from things like filter-no filter or the the usual standard review categories, are there any "problems" that reviews overlooked in using the FF lens on an APS-C?

No. Any FF lens can be used on crop.

consensus on a max angle of a wide angle beyond which distortion

No. That would be personal opinion and there is never a consensus on that. It depends on the person, the lens and the software (and skills of the person)

You also need to decide what you mean by 'landscape'. I have shot more landscapes with the DA*60-250 than anything else.

[pres589]

Quality / price ratio is very good with the Samyang 14 f2.8. DA 15's are good in this way as well, although new pricing isn't as great, though the lens is a notch above the Sy 14 in terms of features and build quality and size/weight. I prefer the older SMC version due to straight aperture blades and the starbursts they bring to the table.

There's that Venus Optics 12mm f2.8 that seems very good although they run around $1000 USD currently and are also manual focus. If I were in a cost-no-object sort of mood I would strongly consider one based on bits I've read about them. Other options out there as well.

What's your budget? Do you believe you need autofocus?

[btnapa]

Excluding fisheyes, is there a consensus on a max angle of a wide angle beyond which distortion and such get to be too much of a pain?

I own the Samyang 14 f2.8. It is a very sharp lens. I use it for indoor and some product photography applications. I used the lens on my K3 and now on my K1. It worked fine on both bodies. I kinda liked it better on the K3 since it was a 21mm equivalent. I know some people use the 14mm Samyang for landscapes but for me it has a little too much distortion and extreme look n my K1. My other wide lens is the 28-105 which is not wide enough. If I had to pick one lens for landscapes, it would be a 21mm range lens. The Tamron 15-30 zoom covers that range I am looking for but it is a little pricy. If your budget allows, go for the 15-30. If you are shooting an APS-C, the 15mm Limited gets a lot of positive press.

[gump]

Quality / price ratio is very good with the Samyang 14 f2.8. DA 15's are good in this way as well, although new pricing isn't as great, though the lens is a notch above the Sy 14 in terms of features and build quality and size/weight. I prefer the older SMC version due to straight aperture blades and the starbursts they bring to the table.

There's that Venus Optics 12mm f2.8 that seems very good although they run around $1000 USD currently and are also manual focus. If I were in a cost-no-object sort of mood I would strongly consider one based on bits I've read about them. Other options out there as well.

What's your budget? Do you believe you need autofocus?

To elaborate a bit. AF is nice but I started with MF in 1967 and I can probably re-learn it. What do i mean by landscape? At the extreme, the mountain and desert "vistas" I have found in the western US. I would like to avoid stitching but want to grab most of what I can without any complicated post-process. My intention is to set up tripod shots, when possible using early or late light. In that regard another question. How "fast" a lens should I be after with a stationary set-up for dawn and twilight shots? No night photos.

[Alex645]

are there any "problems" that reviews overlooked in using the FF lens on an APS-C?

Excluding fisheyes, is there a consensus on a max angle of a wide angle beyond which distortion and such get to be too much of a pain?

Optically, no, using an FF lens on APS-C does not create problems.

No, there is no consensus on max angle in part due to subjectivity and in part because the amount of distortion is often associated to the design of the optics and not just the fov.

I have only one experience with a Rokinon 14mm used on an advanced studentʻs Nikon APS-C. He loved it. I didnʻt. I felt the amount of distortion, chromatic aberration, and lack of sharpness away from center reflected the price of the lens. Maybe it was just his specific lens and not representative of the average Rokinon 14mm, but if I was looking for the ʻperfectʻ wide angle lens, Iʻd be looking at the DA 15mm or 14mm Pentax primes.

[WPRESTO]

About distortion:
1) barrel distortion is a common problem with "rectilinear" UWA lenses. In landscape photography it probably appears most commonly when a camera fitted with an UWA lens is tilted up or down, causing the horizon to be "bowed." Generally it can be fully corrected PP in either LR or PS, with some of the image lost from the corners, which generally is not a loss.
2) then there is what might be called "perspective distortion" where nearby objects at the edges of the frame get stretched or angled in a manner that looks odd. Long, long ago a photomagazie pointed out, convincingly, that this is a matter of your eye(s) not being at the same place relative to objects in the picture that the lens was when the image was taken. To see such an image without the distortion, you must place your eye(s) much closer to either the monitor or the print. This type of distortion is pretty much the same as the converging effect of tall objects when a camera is pointed upward when the shutter was tripped. Such vertical convergence is much more obvious and extreme with an UWA lens and appears with even a very small amount of tilt up from horizontal. "Perspective distortion" is pretty much inevitable in any and all images taken with an UWA lens. To avoid it, compose without large nearby object close to the edges of the frame, and use the camera's internal level to avoid any tilt.

[pres589]

To elaborate a bit. AF is nice but I started with MF in 1967 and I can probably re-learn it. What do i mean by landscape? At the extreme, the mountain and desert "vistas" I have found in the western US. I would like to avoid stitching but want to grab most of what I can without any complicated post-process. My intention is to set up tripod shots, when possible using early or late light. In that regard another question. How "fast" a lens should I be after with a stationary set-up for dawn and twilight shots? No night photos.

This post screams DA 15 to me. It's a great lens with a not so hot max aperture. Your use of a tripod makes that much less of an issue in my mind. f4 isn't the end of the world to me with a tripod.

[Des]

"Perspective distortion" is pretty much inevitable in any and all images taken with an UWA lens. To avoid it, compose without large nearby object close to the edges of the frame, and use the camera's internal level to avoid any tilt.

Or just go with it. Perspective distortion is part of the fun in using a UWA lens.







Incidentally, one UWA option for APS-C which has not been mentioned so far is the forthcoming DA*11-18mm f2.8. Should be a really good lens.

[macman24054]

distortion and such get to be too much of a pain?

The most common problem that causes distortion in any lens is the lens not being horizontally or vertically level. The problem is more severe the wider the lens. I regularly shoot near distortion free hand held shots at weddings with my Tamron 10-24. It is just something you must be aware of.

[pinholecam]

The DA15ltd is unique to Pentax on the apsc format.
I'd get it above all else.

Flare resistance to the point of immunity compared to any other UWA out there.
Beautiful starburst (for the older model).
Uniquely small which means it goes everywhere.

[pres589]

Agreed, the go-anywhere-ness makes the DA 15 a must have. I felt silly for not getting on years before I finally did. I don't understand why the other major SLR companies didn't try to clone something like it.

[csa]

Beautiful starburst (for the older model).

How does one know the difference between the older/new model? I really love the starbursts I've seen with the 15!