Jim, not to start your worries again but I'd like to mention that I am very happy with the focusing screen I have for my 5D2. It works absolutely amazingly well for fast 85, 50 or even a 35mm lens. But at 14/2.8 it gives (almost) nothing. The DOF is just too big. But you'll get to know how to use it I'm sure. When you do it can do very well.
Sorry for posting a ridiculously sized image, this is from last winter:
I had considered making an adjustment to my first lens using shims ("washers"), but decided against it as a violation of warranty if something went wrong, or I accidentally dropped a shim into the lens body!
The great thing is that the lens focuses past infinity. If it were short, that would be awful. But like this, remedies that push the lens elements away from the body are relatively easy to perform.
From my perspective, this is practically a hyperfocal lens -- once the proper calibration is known for a few of the longer distances (infinity is a must, 30 feet would be good to know, and around 10 feet), an intermediate aperture setting will guarantee perfect focus. It's a little easier for close-up subjects, under 3 or 4 feet -- the focus is more apparent in the viewfinder. I doubt the lens will ever be used wide open, especially considering the extreme light fall-off at f/2.8.
Naturally, anyone having Live View is going to solve the focusing without issue. I'm working mostly with 1Ds2, 5D, and 1D2 -- so no LV and images must be confirmed on the computer. Hence, my interest in determining and re-marking the focal distances on the lens' distance ring. I have a 60D, so I can likely use that to establish exact focus point with LV -- that's the next step!
Ordered the Rokinon version this evening. I'm not a a wide angle shooter by any means, but this lens looks like it might be a nice one to try. I have a 5D II and 60D so I will use live view for critical focusing.
Gunzorro wrote:
I had considered making an adjustment to my first lens using shims ("washers"), but decided against it as a violation of warranty if something went wrong, or I accidentally dropped a shim into the lens body!
The great thing is that the lens focuses past infinity. If it were short, that would be awful. But like this, remedies that push the lens elements away from the body are relatively easy to perform.
From my perspective, this is practically a hyperfocal lens -- once the proper calibration is known for a few of the longer distances (infinity is a must, 30 feet would be good to know, and around 10 feet), an intermediate aperture setting will guarantee perfect focus. It's a little easier for close-up subjects, under 3 or 4 feet -- the focus is more apparent in the viewfinder. I doubt the lens will ever be used wide open, especially considering the extreme light fall-off at f/2.8.
Naturally, anyone having Live View is going to solve the focusing without issue. I'm working mostly with 1Ds2, 5D, and 1D2 -- so no LV and images must be confirmed on the computer. Hence, my interest in determining and re-marking the focal distances on the lens' distance ring. I have a 60D, so I can likely use that to establish exact focus point with LV -- that's the next step!...Show more →
My main body use to be the 1DsII as well (I now use 5DMkII) and trying to focus through the viewfinder is absolutely impossible - especially for close up focusing. It can't be done without live-view.
However, if you shoot the typical landscape then shooting hyper-focus makes everything super easy - especially if you can shoot at f/16 (which with a tripod is no big deal). I just set (the focus to 3 feet and f/16 – and that places a total “in focus” distance of 1’3” to infinity! The example below has the bush in lower left corner maybe 2 feet from the lens). Therefore, if you can shoot at f/16, this simplifies manual focusing for landscapes.
Other hyper-focus options - focus at 7ft and f/16 and everything from 1' 8" to infinity is in focus with infinity be in crisper focus - as set on 7ft the infinity "in focus" is from f/5.6 onwards!
As for shooting f/2.8 - I find myself shooting at f/2.8 quite often, such as inside cathedrals, and with very good results. See example.
wfrank wrote:
Jim, not to start your worries again but I'd like to mention that I am very happy with the focusing screen I have for my 5D2. It works absolutely amazingly well for fast 85, 50 or even a 35mm lens. But at 14/2.8 it gives (almost) nothing. The DOF is just too big. But you'll get to know how to use it I'm sure. When you do it can do very well.
Sorry for posting a ridiculously sized image, this is from last winter:
Dave -- Nice examples, thanks! I don't think this lens requires f/16 for great sharpness with most subjects, although for specialized shots like your plane there, it is pretty mandatory. I've been having terrific results at f/8, and surprisingly (as you will see in a moment), at f/2.8 wide open.
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Did I accidentally state earlier that I was coming to an end of my testing? Ha-ha! I'm a big, fat liar!
I've continued working out where the focus points actually are on the helicoid/barrel. Here is a shot of a preliminary stage a couple days ago, shoting how it relates to the measurement on the barrel: http://i25.photobucket.com/albums/c80/gunzorro/IMG_3263.jpg
All these shots are at f/2.8 and PP in LR3 to various extents (mostly involving Canon 14/2.8L v.1 profile, sharpening and some exposure and dodge/burn adjustments). The results seem to indicate that I am now spot-on, as none of these shots was focused through the viewfinder, only by guesstimate of the distances (I'm getting pretty good at this!). The distance markings on the lens above indicate the common "go-to" distances that I use the lens at, but frequently use in-between settings, such as midway between 12' and infinity, just under 6', or half way from 6' to 12' -- the lens has generous DOF even wide open, as you can see. For shorter distances, I use the OVF successfully with lens wide open (closest focusing is about 6" from front lens element).
All shots on 1D Mark II, giving an effect AOV equal to 18mm lens on FF body. All shots at ISO 200 for beginning, and ISO 100 for later.
Besides the early morning light, the lens tends toward yellowish/warm wide open, and becomes fairly neutral at f/5.6 and beyond.
Part of my difficulty in assessing exact focus points seems to be influenced by a front focus shift as the lens is closed down, the result of strong spherical aberration with the sides coming forward -- this incorrectly gives the impression that the lens has greater DOF than it actually does (note Dave's comments above). The spherical aberration sort of blends in such that you wouldn't detect or question it. Far from being a negative, the "horseshoe focus" as I call it (but it really is like being inside a sphere with these retro focus wide angles) is a real asset for making sides and foreground sharp while using wide apertures, and your distant central point of interest is sharp too!
I'm not talking about a lot focus shift, but seems to be noticeable when really paying close attention. That's partly why the "pre-sets" on are invaluable -- I've spent a lot of time assuring that the focus is right and well within the DOF of all aperture settings.
Hope this helps explain some of the quirks you are likely to encounter with this amazing and inexpensive lens.
Here are the remaining shots from today, all shot wide open at f/2.8. Many of these are revisited locations from my posting about a month ago on the Samyang 35/1.4 thread, if anyone would like to compare the different renderings and my approach to framing.
I think that 14/2.8 distortion is that complex kind which cant be fixed other way than via lens profile (PT correction works btw.). Tho PT lens correction is better than Adobe even on things where it shouldnt be.. (means lens have Adobe profile, yet PT corrects better).
I wanted to see how the 14 would do on a crop sensor, so I took out the Rokinon on my Canon 60D. The focal length equivalent is 22.4mm -- still pretty wide. It still has the 14mm DOF, which is extensive.
All shots were pre-focused using my "custom" lens markings on the lens barrel -- no LV or OVF. I will say it is accurate if you do your homework and are good at estimating distances (just takes a bit of practice). And fast to take pictures, with so many subjects the same distance! I sometimes find myself naturally swinging into framing patterns that accomodate these distance settings.