What does this mean?: Lenses now work as they were intended on M9

[skimmel]

I've seen it written several times that lenses now work as they were intended to on the M9.

I've been thinking about this some and trying to get my head around it.

The obvious answer is that a 35mm lens now has an uncropped 35mm angle of view. So, for those of use who grew up with 35mm film (I did), we have true match between focal length and what we're used to. But, I think you can get used to this initial "cognitive dissonance" or, if you've grown up only with digital cropped sensors, it doesn't mean anything to you.

So, is there more?

One thing I noticed when shooting with a 35mm on a cropped camera (I mostly noticed this in my prior Canon days, but should still apply) is that I felt that I got some distortion from the 35mm that I didn't get from a 50mm all else being equal (i.e., filling the frame with subject, etc). That is, I felt that I got better results with full frame portraits shooting full frame using a 50mm lens than shooting cropped frame using a 35mm lens purely on the basis of distortion.

Then there is depth of field at a given subject to camera distance (e.g., to get a 35mm "full frame view" with a 35mm lens on an M8 would require me to stand back farther than I would if used on full frame, thus altering DOF).

Then, maybe there's something else. Something more technical vis a vis lens design and how it matches with full frame. Or something else more cosmic . Or, maybe there is nothing else and the whole issue about full frame is simply related to crop factor and the availability of lenses to get a certain angle of view with a certain aperture.

So, what are people's thoughts about the potential differences between the full frame vs. cropped sensor vis a vis how the lenses used for them might render differently.

(NB: I am not asking about specific lens availability for different crop factors. I also am *not* trying to argue for or against full frame, nor am I trying to defend or attack what I've read on this topic. Just looking for an open discussion on the topic)

 

[Ranger 9]

I think it's mostly just a portentious-sounding-but-meaningless phrase that writers are throwing into M9 reviews because they like the sound of it.

The interpretations you've already proposed are valid ones: "as they were intended" in the sense of "as they work on a film Leica," or "without wasting designed angle-of-view on a cropped sensor." Neither is really relevant to picture-taking, but as you say, there may be a comfort factor in working with what you're accustomed to.

Another possible interpretation would be that "work as they were intended" means "you don't need [as much] software vignetting correction or those dratted IR-cut filters."

 

[Diane B]

They say the same thing about 35mm FF DSLRS LOL. It was always (probably still is) thrown around. The inference is that the lenses were designed for 35mm, thus they will work 'better' or 'as intended' (crop factor, DOF, etc.) on a sensor that is the 35mm size.

 

[trisberg]

Well, if you like to shoot with a super-wide angle lens then there is a difference. Wide angle lenses tend to get slower and heavier the wider they are due to more complex deigns. So a 21-25mm lens with f 2.8 is relatively small and light for the M9. Finding an equivalent lens for the M8 is not possible - you'll have to get a slower lens with some heavier glass that you don't really want or need.

-Thomas

 

[ddk]

My challenge has also been finding a 35mm lens for the APS-C sensor that would render like a 50mm on FF, otherwise I have no other issues with crop factor.

 

[fotografz]

What does it mean?

Depth of field.

Angle of view.

Cost for a comparable angle of view: 6K to get approx a 32mm f/1.4 on a crop frame, a lot less for a 35/1.4 on a FF.

-Marc

 

[jlm]

the main impact is that a cropped camera loses maximum angle of view compared to full frame

 

[nostatic]

My challenge has also been finding a 35mm lens for the APS-C sensor that would render like a 50mm on FF, otherwise I have no other issues with crop factor.

Pentax FA 31/1.8 ltd? That is close (depending on what you mean by "render").

 

[ddk]

Pentax FA 31/1.8 ltd? That is close (depending on what you mean by "render").

Th overall look of the lens.

I see distortions in a 35mm lens that are not there in a 50mm. There's also a distinct difference in the out of focus areas.

I never owned a pentax can't comment on that lens...

 

[skimmel]

Thanks to all for your replies. I think the statement about lenses working "as they were intended" is probably used a lot primarily because it sounds good.

Until this thread, I haven't heard a lot of people talk about distortion before when using 35mm lenses on cropped sensor to shoot what would be 50mm views. I felt like I saw it as well in my prior experience.

 

[PeterA]

Hmm I am wondering what the problem is with "as they were designed to be used" - and have concluded that it is just an issue of ignorance - on the part of those that actually don't understand the very simple notion.

:ROTFL::ROTFL::ROTFL:

 

[fotografz]

Thanks to all for your replies. I think the statement about lenses working "as they were intended" is probably used a lot primarily because it sounds good.

Until this thread, I haven't heard a lot of people talk about distortion before when using 35mm lenses on cropped sensor to shoot what would be 50mm views. I felt like I saw it as well in my prior experience.

It sounds good probably because it IS good.

What always gave me a grin was the claim that a crop frame added to the long end of focal lengths so a 90 became an equivalent 120mm focal length angle of view. Just crop a FF file by 1.33X and you have the same thing. But you can't add extra angle of view at the wide end with a crop sensor camera.

:salute:

 

[Jorgen Udvang]

Th overall look of the lens.

I see distortions in a 35mm lens that are not there in a 50mm. There's also a distinct difference in the out of focus areas.

I never owned a pentax can't comment on that lens...

Nostatic is far too modest on Pentax' behalf. The 31mm f/1.8 Ltd. renders more beautifully than most, if not all 50mm lenses I've seen, and would clearly be one of my favourites if I had a K-mount camera. It's simply very different from anything in that focal length class, but it's also rather expensive.

 

[robsteve]

I think it means the M9 is using the full image circle of the lens, as the lens designers had intended.

Robert

 

[ampguy]

hmm, I haven't noticed much distortion with these 35 lenses (on RD1/M8) vs on film: 35 cron asph, 35v4, 35v3 crons, 35/1.4 pre asph lux, nokton 40/1.4, pentax 43/1.9 ltm (these last 2 are longer effective than 50 I realize).

The most noticeable distortions with 35s I see regularly are with my Hexar AF (still love this lens, and I think part of it is that it lets you focus to 0.5m and I often go that close).

Also, I see distortion in 35/1.4 Noktons, but otherwise a great lens that I hope to try someday.

On the SLR side, I have a great M42 35/1.9 Vivitar with K adapter with no visible distortions, where the new Nikon 35/1.8 AFS distorts quite a bit relative to a 50 on a Nikon crop body.

 

[LJL]

Doing a bit of math for DOF should give you some idea of the differences.

On the M8, a 35mm lens (46.7mm in FF equiv.) at f2.0 shot at 3m will have a depth of field of 0.67m.

On the M9, a 50mm lens (50mm in FF equiv.) at f2.0 shot at 3m will have a depth of field of 0.43m.

May be a trivial amount of DOF difference (0.24m) for some, but there is a difference. Essentially, on a crop sensor camera like the M8, you are having to go to a wider angle lens to get the same view (angle and framing) than you would on a FF sensor like the M9. That will translate to a greater depth of field due to the optical design of the lens. Even though you are cropping the view to approximate the longer lens, you are not escaping the DOF in the lens design.

So, while the view may look nearly the same by using a 35mm on the M8 and a 50 on the M9, the actual optical behavior is different, yielding more possible WA distortion (if any) and greater DOF with the 35mm versus the 50mm.

LJ