Film lenses and mirrorless digital

[sanmich]

I have just bought a panasonic GH-2, mainly for family video, and I wanted to see how my 35mm lenses behave on this one (I have bought some cheap adapters)
Obviously, the RF calibration is not an issue, and I'm limited in my observation to a smaller area of the lens coverage.
The results were sometimes surprising, and I wonder if two lenses performing equivalently on film, could perform significantly away one from another on digital?

 

[unixrevolution]

I don't see how they could perform that differently on digital if they perform similarly on film. Honestly, I've been thinking about it, and I can't think of any reason why they would, at all.

 

[JoeV]

Well, here's one reason they could perform differently on digital but more similarly on film: with film, the "image sensor" is a 3-dimensional layer of gelatin emulsion. Meaning that, even if the optimal plane of focus is non-planar, with film there's a better likelihood that the image will appear sharp center-to-corner, if the plane of focus happens to coincide within the 3-dimensional layer of film emulsion.

Whereas with digital, the image sensor plane is 2-dimensional, and is planarized very exactingly flat, so that minute differences in center-to-corner lens performance are much easier to see than with film.

~Joe

PS: There's also the matter of flat digital sensors needing micro-lenses to optimize off-axis performance, especially important with non-telecentrically designed lenses where the rays fall upon the sensor at other than optimal perpendicular angles, as was common with film-era SLR lenses.

 

[sanmich]

I understand that film is correcting for field curvature while a sensor is not, so when the center of the image is sharp, the digital image in the corners can be less sharp than the image on film.
But what I'm doing when I want to check the corners is focusing in the corners with live view (highly magnified), so this can't be the reason for the discrepancies.

 

[Lightshow]

Also, the sensor is much more reflective than film, and some lenses are not designed to combat that reflection and may cause that light to reflect back or scatter it causing a loss in contrast or causing flare of some kind.

 

[mikemc_photo]

Do they all find infinity at the same focus setting ? Over or under focusing ?

 

[jimithing616]

I have lots and lots of SLR lenses from the likes or Minolta, Konica, Canon, Nikon, Pentax, etc, etc, probably 100 lenses, some great, some crap.... some perform better on digital in my opinion, some the same, not many are worse, a bad lens on film is a bad lens on digital and most of the time a good one is good and a great on is, well you guess it.

Anyway, I don't use electron microscopes or anything to compare pixels, but to my eyes, on my Nex-f3 and my former E-PM1, that is what I have found.

What is interesting though is when some film lenses perform BETTER on digital. Obviously this is not by design, but by some weird chance. There is some talk about this on the interwebs... anyway... To be sure, in my experience, I have never found a great film slr lens to be lacking on digital, can it happen, sure, but its pretty unlikely.

Now coatings are another thing all together, some of the older coatings dont work so great on digital, as mentioned a sensor is more shiny than film, out of my 100 or so lenses I have run into this with only one, a Tamron adaptall 24mm 2.5, love this lens on film, I threw it on my E-Pm1 and flare flare flare, even when I was facing AWAY from light sources. It was strange.

Anyway, thats my 2 cents, and I am by no means an expert!

 

[jimithing616]

Oh, and when it comes to infinity, it depends on the adapter, cheapo ones will be off by one thousand of a MM and they will then hit infinity a hair before the lens is supposed to, therefor going past infinity, I haven't run into any of my adapters not getting to infinity though, this may be by design, they figure they can't get it JUST RIGHT so they make it go past infinity instead of not there at all... makes sense to me I guess. More expensive adapters like ones 100 bucks or more I HAVE HEARD do not do this, they are supposedly perfect... and I have also heard from people with calipers that some of the cheapos are exact too.. which ones, I don't know. But there are posts on MFlenses I believe that were talking about this subject.

hope this helps.

 

[kbg32]

I have had mixed results at best using older lenses with adapters on digital bodies. Other then my Leica M9 and the CV, Zeiss, and Leitz lenses I have had used on my film Ms, they perform great. Adapted lenses from other manufacturers don't perform well at all. I have found that using the lenses designed and made for my M4/3 cameras for example, perform better, then any adapted "legacy" lens I have tried, even Leica M lenses.

 

[podcat]

I have had mixed results at best using older lenses with adapters on digital bodies. Other then my Leica M9 and the CV, Zeiss, and Leitz lenses I have had used on my film Ms, they perform great. Adapted lenses from other manufacturers don't perform well at all. I have found that using the lenses designed and made for my M4/3 cameras for example, perform better, then any adapted "legacy" lens I have tried, even Leica M lenses.

I think its just the quality of the glass, if the sensor is smaller, wouldn't how well the lenses resolve have a much bigger impact as well?

I did a bunch of testing of legacy lenses on m4/3. Konica lenses did well, 50 and 28mm OM Zuiko lenses also did really well (these I can sort of compare because my dad used to take lots of pictures with them on his old Oly and they seem to hold up well on m4/3 as well). I tried out a jupiter-8 lens that also did well despite being obviously flare prone. Finally I tested a 50/1.4 minolta and a russian Helios 44-2 and they were not even close to the quality of the OM and Hexars (although they both have pleasant out of focus rendering, especially the minolta)

 

[one90guy]

I am curious as the reason for using film lens on a digital camera? I have wanted to ask this many times but did not want to start a film/digital slug fest. In using a adapter on a digital camera does this not stop any focus information to the camera?

David

 

[charjohncarter]

I have a mirrorless that is designed to take SLR lenses. And all mine work more than great. Auto-focus, auto-exposure, manual mode and all the rest are great. Because it is a APS sensor the sometimes fall off at the edges for FF sensors with wide angle lenses isn't a problem. This is a 28mm lenses on my mirrorless which is a 42mm 35mm equivalent. I paid $347 for the mirrorless box and $45 (20 years ago) for the 28mm lens.

 

[jschrader]

there is of course one big difference; for film, it does not matter which angle the light has relative to the surface when it hits the emulsion. For digital sensors, it does.

This may have an effect in the corners especially, if it is a wide-angle, except for retrofocus constructions, where the rear lens has a long distance to the film/sensor.

I am not sure if that helps in this case.....

 

[podcat]

I am curious as the reason for using film lens on a digital camera? I have wanted to ask this many times but did not want to start a film/digital slug fest. In using a adapter on a digital camera does this not stop any focus information to the camera?

David

There are adapters that transfer information over, but most don't. Its not a big deal for lenses with manual control, although sometimes it would be nice if the camera remembered what aperture settings you used. If its a lens for an electronic SLR that needs information there are adapters that can handle that but they generally cost a bunch because its no longer just a piece of metal.

There are a few reasons for using film lenses on digital:
1. Price. You can get older film lenses very cheaply. For newer ones of course they are often pricier or the same.
2. Character. Many modern lenses made for digital cameras can have a clinical look and too perfect rendering while you might be looking for some with a more classic look, or just something that stands out a bit.
3. When recording video you often want a manual lens to give you control and dont really need auto focus etc anyway.
4. Build quality. DSLR or mirrorless lenses are usually plastic and not made for manual focusing so if you enjoy that type of thing it is less fun to shoot with.
5. When used on a digital camera with a smaller sensor, such as m4/3 the crop factor changes their usage area. 50mm film lenses work great as portrait lenses on such a camera where they have the same FoV as a 100mm, so if you already have lenses for your film camera they can serve several roles.

The disadvantage is of course that manual focusing often has no support like in a RF or film SLR so nailing it can be harder (some cameras have features like focus peaking which will color in-focus areas and it works pretty well, but not as well as the film alternatives).

 

[cosmonaut]

Some cameras and lens combos just don't work and some do. I tried my Summicron on the NEX7 and the results were not impressive enough to use them together a lot.
In ways I think using what the lens designed for the specific camera is really the best way. I have read digital sensors needs light to fall on them straight on where an old film lens the light can hit the plane at different angles and be fine but its not really a good idea for a digital sensor.
Not to start a war here for those that swear by their old Leica glass. But it makes since.
Also if you are using a full frame film lens on a cropped sensor it seems to me your just throwing away a good portion of what the lens was intended to produce. Just like I would never use a cropped sensor lens on a full frame I mean what's the point of being full frame if you are going to use the wrong lens? But some are fine with it.

 

[Doug]

There's a lot of interest among new and hopeful owners of the latest Leica M (if one considers this "mirrorless") in adapting SLR lenses to it. Live view, the electronic viewfinder, and focus peaking open up new options never before practical on a digital M. Zoom lenses, for instance, or a wide variety of other lenses for particular reasons.

Some of these are pretty bulky, countering the traditional strengths of the Leica, but if it's possible to "go there", some folks will jump right in. 🙂

Adapting lenses from larger-format cameras also adds bulk and weight because the lenses are made to "cover" a larger area. Lenses made to cover the smaller sensor of the camera can be more compact. But, for instance, medium format lenses have long been adapted to smaller cameras on tilt/shift adapters or for other reasons. It all lends more versatility to the gear...

 

[one90guy]

Thanks for the reply's, something that I often wondered about.

David