"That's a helpful clarification. I shouldn't have assumed that everyone knows the circle of good definition is smaller (perhaps a lot smaller!) than the circle of illumination!"
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While that's generally the case as most lenses do fall off in performance toward the edges of the image circle that's not so much the case in many of the more modern lenses, and most lenses also improve in performance somewhat as they're stopped down a bit but there are quite a few exceptions to that rule too. And many designed for 35mm will have baffles designed to limit flare either internally or often at the rear mount of the lens that will restrict the image circle artificially.
The real point of all this is to find out just how many 35mm lenses work well rather than how many don't and you don't necessarily find this out by looking at a chart. You find it out by trying it out and seeing how it actually works in the real world and how it suits your own photographic purpose, and in the process of doing that you might, just might, come up with a new and unique way of seeing something, but you gotta try.
rdeloe wrote:
This point about unit focusing lenses and image circles is interesting. My understanding is that the circle of illumination at 1:1 is twice the size of the circle at infinity -- on any lens. I've never previously seen the idea that the lens design (i.e., whether unit focusing or not) affects this.
It's really only simple trigonometry. Imagine the "light cone" from the rear of the lens projected on the sensor. If you move the (unit focusing) lens away from the sensor, the angle of the cone stays the same and therefore the projected circle gets larger.
Internal focusing lenses often change the focal length with focusing, so it's much more difficult to know how the image circle will behave over the focusing range.
Makten wrote:
It's really only simple trigonometry. Imagine the "light cone" from the rear of the lens projected on the sensor. If you move the (unit focusing) lens away from the sensor, the angle of the cone stays the same and therefore the projected circle gets larger.
Internal focusing lenses often change the focal length with focusing, so it's much more difficult to know how the image circle will behave over the focusing range.
Indeed, but to come back to the starting point for this little tangent, the suggestion was that the amount of vignetting has something to do with whether it's a unit focusing lens. What you wrote was, "Are you focusing much closer with the EF 40/2.8 than the example on the last page? In that case it will give less vignetting because it's a unit focusing lens, which means the image circle gets larger the closer you focus."
My point was simply that the EF 40/2.8 vignettes less at close distances than at infinity because the size of the circle of illumination increases as you approach 1:1; it's not because it's a unit focusing lens. As I demonstrated empirically earlier in the thread, unit focusing lenses behave exactly as expected -- circle of illumination at 1:1 is double the size at infinity.
Anyway, the take-away for people trying lenses meant for smaller formats on GFX cameras is test them at infinity if you're worried about vignetting.
Hello everyone,
I'd have a question re. adapting 67 lenses to GFX.
I'm an architectural photographer so shift is essential to me. Trying to get a set of adapted lenses to use on my GFX 50R, all allowing shift. I'm currently happily using
- canon 24mm ts-e with Kipon EF-GFX adapter
- pentax-a smc 645 35mm with Kipon P645-GFX Shift adapter
and I'm now thinking to get 3 medium - long focal lenght lenses in the Pentax 67 system to oviously make the best of the larger image circle.
Rather than getting a shift P67-GFX adapter I tried mouning a 67 lens on a Pentax 67 to 645 adapter (Pentax), then on the Kipon shift 645 to Gfx. The only 67 lens I own at the moment is a Pentax 135mm f.4 6x7 Takumar which is supposed to be an excellent lens.
It works pretty well stopped down, but when open images are pretty awful, soft and even hazy I'd say. Here's samples of crops at f.16 and f.4.
How do you make sense of these poor results?
Is it (as I suppose) due to the double adapter? Will the quality improve if I opt for one single adapter like the kipon 67-gfx shift?
Before going ahead buying other 67 lenses I'd obviously like to understand / sort this out.
Many thanks for whoever can give me a hand!
P67 lenses are not good enough by today’s standard with sensors in 4-5 um resolution. Better use Zeiss Hasselblad CF 50f4 FLE, CF 100f3.5, CF 180f4 with Kipon HB - GF Shift Adapter. That works very well on GFX. And the lenses have quite sufficient image circle.
Steve Spencer wrote:
The Fuji GF 50 f/3.5 is regularly available for $600 if you shop carefully. Three have sold for that price on eBay in the last three months and one was available here for $625. The Fringer EF lens to GFX adapter is $474, so we are talking a really similar price. Personally, if I didn't have anything yet, I would go with the Fuji 50 f/3.5 unless I knew I was going to adapt other EF lenses.
Maybe I don't check often. The lowest I have seen is $799 from reputable websites. Same all sales here that I have seen are $750 range.
Peter Figen wrote:
Revisiting the Canon 35mm 1.4II on the 100s. It turns out that when used at infinity it vignettes the corners pretty hard but only when stopped down. Shooting wide open or close to it AND when focused fairly close - as in the type of situation where I would use this - for a head and shoulders environmental portrait the vignetting is negligible. For that type of use this lens is extraordinarily sharp even wide open with a beautiful out focus rendering. I'm looking forward to using it that way. At infinity and stopped down the vignette is hard but the image is critically sharp right up to the falloff. So, all in all, another really fabulous solution for a specific type of photography. And the AF is quick, accurate and snappy with the Fringer adapter. For other more standard types of images in this focal range, the 32-64 is a better choice. This contradicts the lens compatibility chart that's been linked several times here. And removing the lens shade made little if no difference. Still, very excited to see this one in action. ...Show more →
Good to know this. I ended up getting Tamron 35mm f1.8 based on another posters review and so far so good. 20211230_Test_Tamron_35_0004 by Vishi A, on Flickr
grasmuc wrote:
P67 lenses are not good enough by today’s standard with sensors in 4-5 um resolution. Better use Zeiss Hasselblad CF 50f4 FLE, CF 100f3.5, CF 180f4 with Kipon HB - GF Shift Adapter. That works very well on GFX. And the lenses have quite sufficient image circle.
The SMC Pentax 67 55mm f/4 (3rd generation) is more than good enough for a GFX 50R camera. So is the 75mm (older version). The 45mm is too soft for my tastes.
This is an opinion based on actually using these lenses, and comparing them against modern GF lenses.
Hello everyone,
I'd have a question re. adapting 67 lenses to GFX.
I'm an architectural photographer so shift is essential to me. Trying to get a set of adapted lenses to use on my GFX 50R, all allowing shift. I'm currently happily using
- canon 24mm ts-e with Kipon EF-GFX adapter
- pentax-a smc 645 35mm with Kipon P645-GFX Shift adapter
and I'm now thinking to get 3 medium - long focal lenght lenses in the Pentax 67 system to oviously make the best of the larger image circle.
Rather than getting a shift P67-GFX adapter I tried mouning a 67 lens on a Pentax 67 to 645 adapter (Pentax), then on the Kipon shift 645 to Gfx. The only 67 lens I own at the moment is a Pentax 135mm f.4 6x7 Takumar which is supposed to be an excellent lens.
It works pretty well stopped down, but when open images are pretty awful, soft and even hazy I'd say. Here's samples of crops at f.16 and f.4.
How do you make sense of these poor results?
Is it (as I suppose) due to the double adapter? Will the quality improve if I opt for one single adapter like the kipon 67-gfx shift?
Before going ahead buying other 67 lenses I'd obviously like to understand / sort this out.
Many thanks for whoever can give me a hand!
The image circle is larger on the Pentax 67 lenses, and as you've discovered you can easily put Pentax 67 lenses on a Pentax 645 shift adapter using the Pentax adapter; it's such a good fit that it feels like it's part of the lens. However, will the adapter you're using allow you to use the larger Pentax 67 lens image circle? If it's designed for Pentax 645 it will only give you 12mm of shift, in other words, no more than if the lens was Pentax 645.
I use and have used many different lenses on my Toyo VX23D with GFX 50R, including Pentax 645 and Pentax 67. My advice is don't bother with Pentax 67. Some of the lenses are excellent on the GFX 50R, notably the 3rd generation Pentax 67 55mm f/4. The Pentax 67 75mm f/4.5 (which is not as sharp as the 55/4 3rd gen, but still very good). Unfortunately the 45mm f/4 Pentax 67 is just too soft. I haven't used your 135mm lens.
For your situation the best option I can recommend if you want to stay with Pentax is the SMC Pentax-A 645 45-85/4.5 (or FA if you prefer that style -- optics are the same). It is without a doubt the best medium format Pentax 45mm lens you can find, and it's a great performer to around 70mm, and still very good at 85mm. The image circle gets larger in the middle of the zoom range, relative to the ends; this gives you a bit more shift room if you have an adapter that can use it. If you want a small and light option at a bit longer than normal focal length, the Pentax-A 645 75mm f/2.8 is superb once you get to f/5.6. It's better than the Pentax 67 75mm f/4.5 (the old version I tried).
+1
The SMC Pentax-A 645 45-85/4.5 is a terrific lens (if well-centered). För me it is as good at 54x36mm (Sony A7RM2 with Mirex adapter) as the Contax Vario-Sonnar 35-70mm at 36x24mm.
bobby350z wrote:
Maybe I don't check often. The lowest I have seen is $799 from reputable websites. Same all sales here that I have seen are $750 range.
This one was available here, but apparently no one wanted it.
Olaf G wrote:
The SMC Pentax-A 645 45-85/4.5 is a terrific lens (if well-centered). För me it is as good at 54x36mm (Sony A7RM2 with Mirex adapter) as the Contax Vario-Sonnar 35-70mm at 36x24mm.
I own both of these lenses as well and am likewise very pleased with their performance when used as shift lenses with my GFX 100S and Sony A7R, respectively.
Although it's still early days with my sample, so I'm not yet prepared to definitively pass judgment on it, the P645 33-55 zoom is performing well for me and the urban and suburban street and alley photography I do, which usually includes significant architectural elements.
Of course, I also photograph late at night, so vignetting and soft corners are potentially much less of an issue for me than other photographers, but so far, so good! As a bonus, it's also noticeably smaller than the 45-85 zoom and significantly lighter, too!
And, it seems, it also suffers less mustache distortion at its wide end than does the P645 35/f3.5 prime, which can be problematic when photographing some scenes.
For grins and giggles, here are a few sample photos I've taken recently with mine:
P.S.: I also concur with Rob above about the P645 A 75/f2.8 prime being excellent performer for this purpose, as well as the DF A 55/f2.8. Unfortunately, the D FA lenses lack an aperture ring, which makes them unusable with the lens mount on my FK VIII rise / fall adapter... <sniff, sniff>
rdeloe wrote:
Indeed, but to come back to the starting point for this little tangent, the suggestion was that the amount of vignetting has something to do with whether it's a unit focusing lens. What you wrote was, "Are you focusing much closer with the EF 40/2.8 than the example on the last page? In that case it will give less vignetting because it's a unit focusing lens, which means the image circle gets larger the closer you focus."
My point was simply that the EF 40/2.8 vignettes less at close distances than at infinity because the size of the circle of illumination increases as you approach 1:1; it's not because it's a unit focusing lens. As I demonstrated empirically earlier in the thread, unit focusing lenses behave exactly as expected -- circle of illumination at 1:1 is double the size at infinity.
Anyway, the take-away for people trying lenses meant for smaller formats on GFX cameras is test them at infinity if you're worried about vignetting....Show more →
What I meant was that because it's a unit focusing lens, we know that the image circle is larger at shorter distance. For internal focusing lenses we have no clue unless we've tried it.
Makten wrote:
What I meant was that because it's a unit focusing lens, we know that the image circle is larger at shorter distance. For internal focusing lenses we have no clue unless we've tried it.
Many thanks for this, and for sharing your folder - that really helps.
Have you checked the files I posted? https://photos.app.goo.gl/YDYZ7QFYBLLFAAjv8
My concern at the moment is less about the shifting feature, but the performance of P67 lenses using both adapters at the same time, and whether that could be fixed using a p67 to gfx shift adapter which perhaps minimizes the risks of lights infiltrations. The performance (even when not shifted) of the 135mm at f.4 is really unexpected with lots of fogging.
About the shift on 67.. actually the kipon P645-GFX allows for 16mm shift so it goes beyond the use of a 645 lens, and I'd be pretty happy having that amount on a 6x7 lens. For instance I'm using it with a Pentax-A SMC 35mm (645) and over 12mm shift it vignettes quite considerably.
grasmuc wrote:
P67 lenses are not good enough by today’s standard with sensors in 4-5 um resolution. Better use Zeiss Hasselblad CF 50f4 FLE, CF 100f3.5, CF 180f4 with Kipon HB - GF Shift Adapter. That works very well on GFX. And the lenses have quite sufficient image circle.
phSimo wrote:
Many thanks for this, and for sharing your folder - that really helps.
Have you checked the files I posted? https://photos.app.goo.gl/YDYZ7QFYBLLFAAjv8
My concern at the moment is less about the shifting feature, but the performance of P67 lenses using both adapters at the same time, and whether that could be fixed using a p67 to gfx shift adapter which perhaps minimizes the risks of lights infiltrations. The performance (even when not shifted) of the 135mm at f.4 is really unexpected with lots of fogging.
About the shift on 67.. actually the kipon P645-GFX allows for 16mm shift so it goes beyond the use of a 645 lens, and I'd be pretty happy having that amount on a 6x7 lens. For instance I'm using it with a Pentax-A SMC 35mm (645) and over 12mm shift it vignettes quite considerably. ...Show more →
Just had a look at the pics. What I see isn't surprising. Lenses that do well wide open are a relatively modern phenomenon. I don't imagine most people who shot P67 with that lens were expecting it to be crisp and contrasty wide open.
Good for Kipon! My Fotodiox P645-GFX t/s adapter only goes to 12mm, which is plenty for 645, but not for P67. Strictly speaking, a P67 lens has an image circle that would allow 18mm of shift on GFX.
I have used the P67 to P45 adapter, and if it's an actual Pentax one, you should have no issues with reflections; I didn't. In contrast, I have yet to use an adapter from any manufacturer that didn't have reflection issues. There are some easy things you can do to test. For example, try making a tube out of a dark, non-reflective material, fitting it in the rear of the lens so it goes from the glass out past the end of the adapter, and do with/without comparisons.
Here's an example of what I mean. This is a lens that I adapted for use on my outfit. I had remove a lot of the guts in the rear and make a new mount. This includes a crucial light baffle. I stuffed this tube in as a test... and it's still there because it works perfectly and I haven't bothered making a new one. Mine is made with telescope flocking, but for a simple test, anything non-reflective that eliminates the possibility of reflections coming from the adapter will do.
Speaking of shift adapters... Is there any such on the market that allows tilt and shift in the same direction? I don't understand when you'd want to use them perpendicularly.
