I just tested a newly acquired Pentax 67 45mm f4 lens on my Fuji GFX 50r using a Fotodiox adapter. Given the 67 to GFX crop factor of .50 I expected to achieve a 23mm equivalent field of view. Instead, it looks almost native 45mm. My Pentax 645 lenses behave like they should with their crop factor (Pentax 645 35mm is very close to my Fuji 35-70 at 35mm, which is about 28mm EFOV. I bought the 67 lens to get a wider-than-28 field of view. What have I missed in the translation? Thanks for any help.
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Adapted Pentax 67 45mm f4 lens to Fuji GFX 50r not wide given crop factor
- Thread starter diforbes
- Start date
wallpaperviking
Member
Yup, still a 45mm lens, so roughly a 36mm (full frame equivalent) on your GFX. The only difference here is that it has a much larger image circle and therefore gives you the option to shift if required..
Your example of the Pentax 645 35mm demonstrates this but also has a larger image circle if you needed to shift.. ..
AlanS and Wallpaperviking are correct. focal length is focal length, regardless of format. So to break it down, a 45mm lens on apsc is the same 45mm as on a 4x5 camera. the difference is the each 45mm is designed with the particular sensor/film size in mind. As you jump between formats using adapters, you aren't changing focal length you are changing the size of the projection each 45mm can render. If you were to grab a 45mm FF lens, you would notice the angle of view should look the same, but as it was designed for a format smaller than mini medium format, you might see the edges of the image circle, or vignetting, as the designer didn't plan on you using it on a larger film/sensor space than 35mm. This is somewhat subjective as some lens makers do use larger image circles for a given format depending on what they are trying to achieve, so a canon 45mm might have a slightly smaller image circle than say a nikon or sigma 45mm even though they are all covering 35mm format...
In your case, you picked a much larger projection lens in 45mm, so now if you have the right equipment, you would have the ability to shift that lens similar to a view camera.
If you want to get something closer to what the Pentax 67 45mm renders natively there are lens adapters that have focal reducing lens elements in them. You'll get something closer to the 23mm field of view, but at the likely expense of reduced image quality.
In your case, you picked a much larger projection lens in 45mm, so now if you have the right equipment, you would have the ability to shift that lens similar to a view camera.
If you want to get something closer to what the Pentax 67 45mm renders natively there are lens adapters that have focal reducing lens elements in them. You'll get something closer to the 23mm field of view, but at the likely expense of reduced image quality.
rdeloe
Well-known member
What everyone else said... focal length is focal length.
45mm is a tough focal length in adapted lenses. I tried a P67 45mm on my GFX 50R outfit and was disappointed by the results. The colour and contrast are nice, and distortion is manageable. However, the lens is not resolving detail at a level I considered good enough to make it worth keeping the lens. I haven't tried a P645 45/2.8, mostly because I've never read a report that it's particularly good. In contrast, the P645 35/3.5 (A version) is excellent and a mainstay in my work.
Without a doubt the best adapted 45mm focal length I've used is the P645 45-85mm lens. It's a bit heavy and the A version has a rotating front element, which I don't love, but the lens is a really strong performer.
45mm is a tough focal length in adapted lenses. I tried a P67 45mm on my GFX 50R outfit and was disappointed by the results. The colour and contrast are nice, and distortion is manageable. However, the lens is not resolving detail at a level I considered good enough to make it worth keeping the lens. I haven't tried a P645 45/2.8, mostly because I've never read a report that it's particularly good. In contrast, the P645 35/3.5 (A version) is excellent and a mainstay in my work.
Without a doubt the best adapted 45mm focal length I've used is the P645 45-85mm lens. It's a bit heavy and the A version has a rotating front element, which I don't love, but the lens is a really strong performer.