Diffraction and Voigtländer Lenses: is it really a problem?

All lenses suffer from diffraction. There's no getting around it. As we stop down, the light rays begin to interfere with each other, reducing sharpness. Pixel size also has a bearing as smaller pixels will suffer more from the effects of diffraction than larger pixels.
So does that mean we should stop using smaller apertures? How big a problme is it?
#fujifilm #voigtlander #fujinon #cosina #primelens #27mm #photographybypetercharles

[@davidbrighten2572]

Thanks Peter! Good video and message. Really appreciate your work and channel

[@torb-no]

Diffraction is very individual to specific lenses. For example, AFAIK the 27mm Voigtlander is quite sharp at f8 for example. So I'd test every lens instead of assuming (though, maybe you already did that).
Anyway, I think it's interesting how different lenses make different tradeoffs. All the Voigts for Fuji are incredibly compact for their given aperture, and something's gotta give and I guess that in some cases is diffraction.
As for f22, I find that to be an mostly pointless aperture (my Fuij XF 16mm f2.8 also has that), and in my experience you typically use it to not get too much light, but I find using electronic shutter with ultra fast shutter speeds to be a far better solution to that specific problem (unless you specifically want motion blur). I suppose if you want something both super close *and* far away in in focus it would work, but in that case I think I'd consider focus stacking.
Anyway, always appreciate your videos on the Voigtlander lenses! They're so underrated!

[@SummersSnaps]

The actual main problem with this specific voigtlander lens is field curvature (it suffers it quite terribly making it a not so great landscape lens etc). Diffraction is just something all lenses suffer from and it can be quite interesting how early it rears its head on some lenses (f2 is peak for Viltrox 75/1.2, after this diffraction is seen).

[@photographybypetercharles9939]

I keep hearing about the field curvature problem, but I would hardly use the word "terrible". I tested the lens curvature problem by shooting a large brick wall of the gymnasium of our local school. I have to enlarge the RAW images to max to see any curvature and we have still have to study the image almost brick by brick to see it.
In my test, using a horizontal slice across the middle of the frame, it shows up as a sharp centre, then as we move out towards roughly a third of the way it gets a bit softer, then it sharpens up again as we get closer to the edge of the frame then softening right at the edge. This was evident using an image shot at f4 where this lens is the sharpest.
Stopping down doesn't eliminate it as I see it at f16 as well as f1.2, though for obvious reasons, it's much harder to see at the aperture extremes than in the f4 to f5.6 range. We really have to strain to see it at f1.2 due to the overall softness of the image. Diffraction at f16 also makes it hard to detect. If I didn't know where to look for the softness, I probably would not be able to detect it at f1.2 or f16.
When I view the f4 wall RAW image filling a 27" monitor, I can't see it. I have to enlarge the image to max and study it.
Frankly I find the field curvature issue to be a tempest in a teapot. The typical enthusiast will not see it in their photos, especially considering the softness wide open and diffraction when stopped down. Those issues effectively mask the field curvature.

[@SummersSnaps]

@@photographybypetercharles9939 I would actually use the word terrible, when considering the price of the lens. Out here in Australia it is a $1000 lens, not cheap. I think your test may be somewhat flawed and one sided in revealing how much it can impact an image, or your copy variance is displaying a fairly mild version of it. Of the actual images I have seen (a friend has this lens), the overall image just doesn't make sense and displays a pretty flawed result. For example, on a stopped down f5.6 landscape scene, where the focus point is a few meters away in the center, this area is fine and resolving detail and sharpness nicely, but as you scan away from the center you're met with poor cruddy mushy details on content that exists on the same focal plane and really should hold the same quality and clarity, and then as you continue to scan the image further the stuff in the corners that is far away from the original focus point (but closer to the photographer) is pin sharp!, but then the images deteriorates again as you work back from the corner (towards the origin of focus... which is the opposite of what you'd expect). Basically the focal plane seems all over the place, it's in two places at once (and the extremes of one another), and if taking just center and corner sharpness into account you can be fooled to thinking it is scoring and performing well.
Of course it depends on the context in the scene, and how good the image is in the first place and whether it merits studying properly or just a simple grab shot. Some shots it is harder to see, but on others its quite blatant.
Wide open portrait work with this lens shines, in fact the curvature is possibly even assisting with that 'pop'. But then lens becomes a bit of a one trick pony, nice for wide open or close to wide open work. Thinking it can be a suitable allrounder lens is not going to please many. I'd grab one for a couple hundred bucks, but not 4 digits...
From a reputable brand like Voigtlander I think we all expected better than this and likely contributed to the backlash. Really its behaving like a low tier priced chinese lens.

[@franciscoscaramanga2342]

Hello, There seems to be a bug in the last software updates for the XT5 and XH2s cameras. All Voigtlander lenses register f22 when you select the widest aperture. I have a 35mm Nokton, 35mm Ultron-Macro and the 50mm Nokton and they all behave the same way on both my Fujifilm cameras. When ever you choose the widesd aperture it registers the closest aperture on the EXIF data.

[@photographybypetercharles9939]

Yes, I have experienced the same thing on my X-H2. The X-Pro3 is fine though and it's on that camera body that I use these lenses the most.

[@franciscoscaramanga2342]

@@photographybypetercharles9939 I think the issue is only with the last firmware update. The X-T5, X-H2 and X-H2s have been updated recently but not the X-Pro 3.

[@photographybypetercharles9939]

My X-H2 has the latest firmware as well.

[@gartk69]

Hi Peter, I want to have a small compact lens for travel but have never shot with a manual lens yet. I purchased the new Pergear 25mmf1.7 and I’m still waiting for it to arrive. If I can get used to that lens I would like to purchase the Voigtlander 18mm f2.8. Does having the electrical contacts really help? Is the Voigtlander brand a lot better than the much cheaper Chinese brands?
Your thoughts would be greatly appreciated.
Thank you for your time, Gary

[@davidbrighten2572]

Hi Gary, I have many manual lenses, about 1, including Pergear lenses. I prefer manual over autofocus. The Pergear lenses are acceptable, low cost and fun but are soft, have field curvature issues and low contrast. They are similar to older lenses. The electrical contacts on Voigtlander lenses are useful for EXIF data and make it easier as you don’t have to manually select the lenses. They also trigger focus aids. That all said - is it necessary? No. You can set up a button on a Fuji camera to call up focus assist (zoom in for focus). I own 7 Leica M Mount Voigtlander lenses and I use those along with the 23MM F 1.2 X mount lens. I suggest using any manual lens and adapting to Fuji. The X mount lenses from Voigtlander are excellent and great value. You can’t go wrong either way.

[@photographybypetercharles9939]

Except for the lack of AF and the stopping down of the aperture, Voigtländers behave like Fujifilm lenses on manual focus. The real difference over the cheap lenses is twofold: optical quality and the information they feed back to us in EXIF and in the viewfinder.

[@gartk69]

@@photographybypetercharles9939thank you, now I’m more excited about Voigtlander.

[@gartk69]

⁠@@davidbrighten2572thank you so much for your insight. Now I’m really excited to get the Pergear and perhaps the Voigtlander after.

[@torb-no]

The value proposition of the contacts on Voigtlander are:
- You can set up the camera to automatically zoom in whenever you change the focus (and it shows you the entire image by half pressing the shutter). Of course you can also do this by simply using a button when it comes to other lenses. I think this is the most important difference. For slow moving or static subjects I think it's the most reliable way to focus. (This is called Focus Check by the way)
- You get the aperture information in the viewfinder so you can see it without taking the camera away from your eye and look at the lens.
- Since the camera gets the focal length from the lens it can automatically engage the in-body stablelization (this can also be done manually but you have to remember to set it up correctly)
- The camera can also display a focusing scale in the viewfinder/lcd because of the contacts.
- Your files get the full EXIF data for the lens (lens name, focal length aperture)
Personally however I think the biggest advantage of the Voigtlanders are that they are simply amazing lenses optically. That is to say, not perfectly sharp or whatever, but they render our beautiful images. I think they espescially have nice rendering color, nothing else I've tried have colours like the Voigtlanders. This is a bit subjective of course.
And their build quality is out of this world as well. If you want something really small close to the 25mm, Voigtlander also makes a 27mm f2 which I think is such a gem of a lens. It has the same housing as the 18mm, so really compact and nice, yet it is still f2. I'm amazed by having such quality in such a small package. Wonderful lens!