The world's widest 1:1 macro lens

[Bjørn J]

Chinese company Venus Optics has launched a 15mm lens with 1:1 macro capability - and  6mm shift when used on DX-sensors.
http://photorumors.com/2015/06/23/venus-optics-announces-the-laowa-15mm-f4-the-worlds-widest-11-macro-lens/
I don't know anything about the quality of Venus lenses, but it's an interesting idea.

[Bjørn Rørslett]

The presentation tells a skewed version of reality. The background sharpness is mainly a function of magnification of detail, so depth of field will be minimal when you get close despite the short focal length. Perhaps setting the lens to f/32 imparts a rough indication of what the background might be, at the expense of killing all foreground detail.

This single factoid is more important though: Min. working distance     0.47 cm (1:1)

Translated to normal language this means you do well in leaving the petal-shaped hood at home, because you can never use it for close-up. Plus getting your close-up subject properly illuminated will be a true challenge.

Price is pretty low, though ....

[Michael Erlewine]

If this new offering from Venus is anything like their 60mm Macro x2 lens, forget about it. The focus throw is probably going to be <90-degrees, which makes it pretty much impossible for a WA-Macro lens to focus. I sent their 60mm lens back. It was roughly sharp, but poorly corrected, and, as mentioned, just about impossible to focus... and I was on a tripod in good light.

I wish the big companies would produce a rectilinear fisheye lens of about 15mm or so that had a long focus throw, and was as corrected as these fisheye lenses ever are, which is not much.

[Erik Lund]

If this new offering from Venus is anything like their 60mm Macro x2 lens, forget about it. The focus throw is probably going to be <90-degrees, which makes it pretty much impossible for a WA-Macro lens to focus. I sent their 60mm lens back. It was roughly sharp, but poorly corrected, and, as mentioned, just about impossible to focus... and I was on a tripod in good light.

I wish the big companies would produce a rectilinear fisheye lens of about 15mm or so that had a long focus throw, and was as corrected as these fisheye lenses ever are, which is not much.

Indeed its about 90 deg Focus throw...but for a 15mm... it's much different 'feel' than a 60mm lens the optics don't need to move at all, almost anyway 

Re: --- a rectilinear fisheye lens... ----
You must make up your mind its either or - You can't have both

[Bjørn Rørslett]

For close-up work one really needs either a fairly long lens, around 100 mm or so for FX, to get a decent working distance, OR, a lens with the shortest possible focal length (< 1-2 mm) to get increased depth of field. However, with the latter case you will have almost no working distance at all *and* the format coverage is tiny. Really tiny. So tiny that m43 suddenly looks like a 4x5" in comparison.

I guess this is the Heisenberg uncertainty principle applied to photography. Or in the vernacular version: There is no free lunch. It's either-or.

[Michael Erlewine]

I find myself using the Nikkor 16mm rectilinear fisheyelenses (I have the earlier on one as well) quit often, which are not circular fisheye lenses. I would like an Otus-standard one of those non-fisheye fisheye lenses, which I realize is almost impossible to build.

The 24mm Sigma ART lens is quite useful in that respect, because you can get quite close 9.84" (25cm). Here is a quick shot I took this morning of some Evening Primroses in our yard, which shows that this lens does a decent job until the Zeiss Otus version of this length of lens comes along.

[Asle F]

For 1:1, it can be hard to use. But for environmental closeups, I like the idea. Today I use 20mm/3.5 and 24mm/2.8 with K1-ring, but a lens that can focus continuously up more close than I need, would be a good thing.

It's called macro lens, and with macro as in big, it is not a bad description, because the lens is big, probably too big for much of this usage. I'm skeptical for several reason. Michael mention some of them.

[Michael Erlewine]

Not understanding what you want me to mention. Perhaps you could rephrase the question please.

[Erik Lund]

I find myself using the Nikkor 16mm rectilinear lenses (I have the earlier on one as well) quit often, which are not circular fisheye lenses. I would like an Otus-standard one of those non-fisheye fisheye lenses, which I realize is almost impossible to build.
...

It's not called rectilinear, it's a 'Full Frame Fisheye' lens the 16mm f/2.8 180 deg diagonal capture and the old 16mm f/3.5 170 deg only straight lines though the center remains straight.

Rectilinear lenses are corrected so that straight lines remain straight even when they are off center...

Money can buy anything - Almost

[Erik Lund]

For 1:1, it can be hard to use. But for environmental closeups, I like the idea. Today I use 20mm/3.5 and 24mm/2.8 with K1-ring, but a lens that can focus continuously up more close than I need, would be a good thing.

It's called macro lens, and with macro as in big, it is not a bad description, because the lens is big, probably too big for much of this usage. I'm skeptical for several reason. Michael mention some of them.

The 20mm 3.5 Ais can be modified for close focus at 18 cm to the film plane, it's just a small cut with a Dremel

[Asle F]

Not understanding what you want me to mention. Perhaps you could rephrase the question please.

I'm sorry. It wasn't a question. It was a misspelling, it should have been: "Michael has mentioned some of them."

[Asle F]

The 20mm 3.5 Ais can be modified for close focus at 18 cm to the film plane, it's just a small cut with a Dremel

It is easy for you to say

I have seen a post about that in the old nikongear. If my memory serves, someone stated that the same could be done with the 24mm/2.8. But I do not remember how you did it. And of all my lenses, the 20mm/3.5 is the one I do not want to destroy.

[Bjørn Rørslett]

Both 20/3.5 and the 24/2.8 will benefit in their close focusing capability if visited by Erik's Dremel    

[Erik Lund]

My 20mm 3.5 is actually the lens that has come closest to getting destroyed during a modification - when gluing in a small piece of tube, for enabling the aperture follower to the added extension of the lens, I accidetially dropped a large drop of super glue into the aperture blades... a loud arghhhhhh followed by frantic fiddeling with tools and more or less ripping the blades out of the aperture housing, soaking them in Acetone... it took some time before the lens was in one working piece again now with the cleanest aperture blades ever

[Bjørn Rørslett]

I did a little more snooping on the Venus website in order to understand the alleged claims for this 15 mm lens.

Apparently they used a Nikon D800E for the published sample photos. The lens is not CPU-enabled and thus no meaningful information about how far the lens is stopped down is revealed.  However, judged from the sharpness of which dust and grime on the 800E sensor is exhibited, it must have been stopped down very far. My guess is that they have gone the entire way down to f/32 and had to add flash to the main subject to get acceptable shutter speeds. The overall low contrast  points to the same conclusion.

The lens might be quite sharp, if the aperture setting was minimised, but it certainly obeys the law of physics. So the depth of field is, even at the assumed f/32 setting, quite restricted in the near range. The short focal length means blur circles are smaller thus an indication of what the background looks like can be seen, but with no real sharpness to it.

There is no free lunch. Buying an ultrawide lens in order to get a "deep field" really does not work. You will still be left with an illusion. Even advertising writers have to admit to this basic fact of life.