[Jimfear]

So I had a chance to borrow a K20D and 2 lenses from a friend, forum member Jean-Baptiste thanks!, and I couldn't resist testing some lenses. She has a Zenitar 16mm that I was interested in comparing to my Sigma 16mm, and I was also happy (but crappy, as you shall see) to do a shootout between my new K50/1.2 and my former workhorse the K50/1.4 and as an added bonus I threw in her M50/1.7. All tests done in a haste so some things weren't checked as thoroughly as the should have been. This was not a controlled enough setting to say anything about colour or contrast so I'll leave that out.


The first shootout I did was between the two fisheyes:

- MC Zenitar 16mm f2.8 Fisheye
- MC Sigma 16mm f2.8 Fisheye Filtermatic



I tested at infinity and at the Zenitars minimum focus distance, the sigma focuses much closer. At infinity crop from center and corner, though it can hardly represent the real corner performance as these are both full frame lenses. At minimum focus only center crop. Not entirely sure if the Sigma infinity focus is the same as the Zenitar so I don't know if it is correct but it does not make much difference as the DOF is so great with these lenses anyway. Now to the shootout:

Zenitar above, Sigma below, 100% crops.
Zenitar vs Sigma

Full test scene infinity:


Full test scene Zenitar minimum focus distance:


Sigma minimum focus distance (I can post a crop series at request):



My conclusion:
Center, the Zenitar is a solid performer, it is not bad, but it also doesn't improve much with stopping down. At 2.8 and 4 it is sharper than the Sigma (more so at 2.8 than at 4), but after that the Sigma improves greatly and surpasses the Zenitar. At "corners" there is not much difference, maybe a slight edge to the Sigma over the whole range but it is hardly noticeable. At Zenitar minimum focus it's the same story, not much difference but this time with a slight edge to the Zenitar except for at 2.8. In practice this means that Zenitar shooters can allow themselves to be less alert on what aperture they are using because the performance is pretty solid. Sigma users on the other hand should really stop down a little to improve sharpness (and contrast I can say from personal experience).



So to the second shootout:

- smc Pentax 50mm f1.4
- smc Pentax 50mm f1.2
- smc Pentax-M 50mm f1.7

I was in such a rush I forgot to take a picture of the lenses but I took one later of the two I own. I guess it's quite easy to find a picture of the M50/1.7 so it doesn't bother that much.



Just center crops at most apertures. The 1.2 lens has a half stop between 1.2 and 2 that I'm not sure exactly what it represents but I guess it's somewhere in the range of 1.4-1.8. Also you will soon see that I didn't get the focus right on the 1.2 lens, the 1.2 picture is in focus but the rest of the series is a little out of focus and this affects the results.

100% crops:
K50/1.2 vs K50/1.4 vs M50/1.7

Full test scene:


My conclusion:
The K50/1.4 seems to only improve as we go up the aperture range, something we cannot say about the two others. It is also reasonably good wide open, but so are the others. The M50/1.7 might have a slight edge in a wide open comparison, but what I would really like to see is how the K50/1.2 compares stopped down half a stop, sadly this is where I should have been more thorough in checking the focus so we cannot really compare them. You will notice how the 1.2 pic is sharper than the two following in the series. Up to 2.8 I would say the M50/1.7 has the edge on the two K's, ever so slight an edge but it's there. After that the M50/1.7 seems to reach its peak and stagnate. At 2.8 to 11 they are all very good but after that both the K50/1.2 and the M50/1.7 seem to lose sharpness, the M50/1.7 suffering more from this. The K50/1.4 seems to take an easy victory in this battle, but in the 4-5.6 range they are all very close and I will have to redo the test with the two K lenses making sure that they are both in perfect focus to be able to call this conclusively. As for now, the K50/1.4 is reigning champion.


Special thanks to Elmer the Elephant for his kind cooperation.

[stevebrot]

Wow...that Sigma does focus close. Nice looking lens too. I was a bit surprised that you did not see improvement with stop-down on the Zenitar. I have not done a test series with my copy, but by reputation it is supposed to be fairly soft at f/2.8, significant improvement at f/5.6 and excellent at f/11-f/16. (I seldom shoot mine wide open.)

My experience with the Zenitar has been that even though DOF is good, attention to focus is very still very important if you want sharp pictures. This is particularly true for distances under 3 meters. It was not until I did some shooting with the Zenitar and split image on the Katz Eye focus screen that I realized that what appeared to be in focus wasn't. The problem is the small viewfinder image combined with the short focus throw.

Would you consider doing the test using at 20x the focal length (32 cm) using a flat target (newsprint or lens test target) and best of 5 for the focus?

Steve

P.S. If you still have the lens, you might want to do Jean-Baptiste a favor and check the infinity focus at the horizon using the viewfinder on one of your film bodies. Mine was out quite a bit and required adjustment.

[Jimfear]

Thanks for the input.

I could very well do the test using a flat surface. However during the winter we do not live in the same city so this will have to be done next summer if I don't happen to meet someone else that is willing to loan me a K20D and a Zenitar. Pentax seems to be scarce around here. I did some quick test shots but I did not take into account that the lens could missfocus. Jean-Baptiste has an MX of her own so she could probably check the focus herself, to my knowledge she hasn't noticed anything strange going on with the focus. But it newer hurts to check.

The Zenitar is not at all bad from 5.6 upwards, it just doesn't show the same improvement that the Sigma shows (which is outright horrible wide open if this was in fact in perfect focus). You could do a quick series testing if your copy shows significantly more improvement when stopped down. After hearing that it reaches its peak at 11-16 I regret not testing at all apertures.

[stevebrot]

Thanks for the input.

I could very well do the test using a flat surface. However during the winter we do not live in the same city so this will have to be done next summer if I don't happen to meet someone else that is willing to loan me a K20D and a Zenitar. Pentax seems to be scarce around here. I did some quick test shots but I did not take into account that the lens could missfocus. Jean-Baptiste has an MX of her own so she could probably check the focus herself, to my knowledge she hasn't noticed anything strange going on with the focus. But it newer hurts to check.

The Zenitar is not at all bad from 5.6 upwards, it just doesn't show the same improvement that the Sigma shows (which is outright horrible wide open if this was in fact in perfect focus). You could do a quick series testing if your copy shows significantly more improvement when stopped down. After hearing that it reaches its peak at 11-16 I regret not testing at all apertures.

I am not a big Ken Rockwell fan (major understatement), but this old test of the Zenitar 16/2.8 vs. Nikon 10.5mm fisheye is the closest thing I have found to a real lens test of the Zenitar:

Zenitar 16mm Fisheye

Unfortunately he mixes bodies/sensor sizes in the comparison, but it is still interesting from the perspective that he has shots from center and edges at multiple apertures for the Zenitar.

Steve

[Jimfear]

I think Ken Rockwells test shows about the same as my results, some improvement between 2.8 and 5.6 but after that nothing spectacular happens. Corners on the other hand show something completely different, Rockwells test shows corners better as they are full frame.