OK to use lens adapters?
- Thread starter zm15
- Start date
In general adapters that do not have optical elements (no glass in the physical adapter) have not been known to reduce image quality. Mine certainly don't. Adapters with glass may reduce the image quality, but only if you get a low-quality adapter whose glass is distorted/smeared/hazy/blurry etc. Most of the GH1 owners I've interacted with love their adapted lenses. I have a Minolta AF adapter to use a 50mm f1.7 and I can't complain; I love that lens.
Thanks for the info!
I'm looking at either a 'nifty 50' from nikon, a $100 Nikon 50mm, or the Panasonic 20mm. Between these two, which is a better lens for a beginner doing general 'around the house' video and pictures?
ahhh, i forgot about that. So i'd need to look for a 25mm nikon to get that 50mm equivalent.
Being to to this m4/3's world, it seems like alot of the great lenses, like a Nikon 50mm, simply can't be used the same way they are on a Nikon for instance. How is this overcome since you have to look at lenses differently?
EidolonFilms
Well-known member
While the 50mm will have the same field of view as a 100mm, the characteristics of the lens do not change. So for example, using the 20mm 1.7 pancake or a 25mm lens on the GH1 will give you a field of view = 40 or 50mm in full frame terms, but they will still display the image characteristics of a wide angle (which 20 and 25mm are moderately wide). Try it yourself. Shooting an CU portrait with the 20mm results in slightly unflattering and distorted faces. Put on a 50mm, and suddenly the face looks much nicer. This is because the 50mm is not a wide angle. Only difference is that you would have to step back further to get the same field of view as on a full frame camera.
So definitely consider the image characteristics of certain focal lengths when buying lenses, not just the field of view. It goes the other way as well. A 100mm lens can "see" farther than a 50mm and will compress things more as well, even though you could say a 50mm = 100mm on the GH1. It's just that the image circle coming from the lens is getting cropped by the smaller sensor, nothing more. So there is still good reason to own a 50mm lens in addition to a 25 mm.
So definitely consider the image characteristics of certain focal lengths when buying lenses, not just the field of view. It goes the other way as well. A 100mm lens can "see" farther than a 50mm and will compress things more as well, even though you could say a 50mm = 100mm on the GH1. It's just that the image circle coming from the lens is getting cropped by the smaller sensor, nothing more. So there is still good reason to own a 50mm lens in addition to a 25 mm.
Barry_Green
Moderator
But... that's exactly the issue. People think the lens is creating the perspective distortion, and it's not. It's the distance from the subject that creates the perspective distortion. Frame up a face on a 50mm on a full-frame camera, and stand in the exact same position and frame it up with a 25mm on a "2x crop" camera, and you'll have exactly the same perspective rendering. The only time you get distortion is if you try to use a wider-angle lens closer than the field of view would dictate.
Use a fisheye, and a telephoto lens, stand in the exact same place and shoot a scene. Then crop the fisheye image down to where it's showing the same field of view as the telephoto, and guess what -- you'll have the exact same perspective! No additional distortion. The perception of distortion with the wide-angle lenses is because people stand closer to the subject when they use them.
Barry_Green
Moderator
A simple way to test it is to use a GH1 with its extended optical zoom feature. Put the Lumix 7-14 on there, zoom to 14mm with EOZ off, and take a shot. Then, with the camera exactly where it was, zoom out to 7mm and turn the EOZ on. The result will be indistinguishable (other than the EOZ shot having slightly deeper DOF due to using a wider focal length). But perspective and distortion and "big nose" effect will be identical, if the camera position hasn't moved.
EidolonFilms
Well-known member
Interesting. I never knew it worked this way. I always thought that the wide angle lenses would look different even cropped in. But I still think the 25mm won't replace the 50mm in m4/3. If you are 10 ft away from your subject, the 25mm will give you a wider field of view than the 50mm at the same distance. So if you wanted the same field of view as the 50mm, you either have to 1.) Move in much closer, or 2.) Crop the image shot with the 25mm to match the FOV of the 50mm. #2 is not possible really with video, and #1 results in the dreaded distortion, because now you are that much closer to your subject. Or am I still missing something here?
The only disclaimer for the fisheye vs telephoto lens example is that lenses with shorter focal distances typically have other distortion characteristics inherent to their design, like barrel distortion, of which a fisheye is an extreme example.
What does EOZ do and where do you turn in on?
Actually, this is not the case. A shot taken with an MFT cam + 25 mm lens will roughly have the equivalent FOV of the one taken from the same distance with an FF cam + 50 mm lens (assuming aspect ratios are the same).
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Barry_Green
Moderator
Well, I mentioned the fisheye and telephoto because somewhere on the web I saw where someone had actually done that exact thing; had shot on a fisheye, and then a telephoto, and extracted the face out of the center and blew it up to where it was the same size in the telephoto shot, and ... the distortion was exactly the same. Blew my mind.
But yes, in general the fisheye's unique characteristics are going to lend it curvature on the sides that you won't see in a rectilinear-designed lens.
But yes, in general the fisheye's unique characteristics are going to lend it curvature on the sides that you won't see in a rectilinear-designed lens.
Barry_Green
Moderator
Extended Optical Zoom. On the GH1 it only works in stills mode, and you have to choose a smaller picture size to get the full 2x optical zoom-in effect.
Barry_Green
Moderator
A 50mm on a "1.0 crop" camera, and a 25mm on a "2.0 crop" camera, when shot side-by-side at the exact same distance towards the exact same subject, will result in exactly the same pictures (in terms of field of view and perspective). But there will be a difference in the depth of field; you would have to account for the DOF difference inherent in the focal length difference. So open up the f-stop 2 stops on the "2.0 crop" camera, or stop down the f-stop on the "1.0 crop" camera, and you'll have absolutely identical images from both cameras.
Ah, OK. I'm in video production, so I rarely use the still capability of the camera, so it doesn't really apply to me.
Barry_Green
Moderator
Right -- it's annoying that it exists but is only available for stills. On the new GH2, it's available for both video and stills.
If you want to experiment with the concepts we're talking about here, you can use the "digital zoom" on the GH1 to replicate the field-of-view differences, but the images won't be nearly comparable in sharpness because the digital zoom is... well, it's a resolution-devouring digital zoom, after all.
If you want to experiment with the concepts we're talking about here, you can use the "digital zoom" on the GH1 to replicate the field-of-view differences, but the images won't be nearly comparable in sharpness because the digital zoom is... well, it's a resolution-devouring digital zoom, after all.
Peter J. DeCrescenzo
Veteran
On a related note, refer to the DMC-GH2 high-quality "Extra Tele Conversion" feature for stills & video, described on p.67 in the user manual:
http://dlc.panasonic-europe-service.com/EUDocs/
http://dlc.panasonic-europe-service.com/EUDocs/