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Contax G2 + GA1 Mount Adapter + Zeiss Planar T 50/1.4

saspencr

Well-Known Member
Is this combination (G2 + GA-1 Mount Adapter + Planar T* 50 f/1.4) possible? If anyone has experience with it, focusing, etc, I would be interested. Seems this would place the G2 as an even better available light camera. scott
 

saspencr

Well-Known Member
"GA-1 Mount Adapter -Allows usage of the Carl Zeiss T* lenses on the Contax G1 or G2. Focus distance is referenced from the G1's focus system and manually translated to the SLR lens."

"... manually translated ..."? What does this mean?
 
R

rickd

Hi Scott

I don't own the adapter, but believe that the G+50/1.4 combo is certainly possible. What I think you have to ask yourself is whether the utility of an extra stop is worth the hassle of taking a distance reading from the camera then manually setting it on the lens using its engraved marks, then composing your shot and hoping that the distance reading is accurate enough.

OTOH if you're working close in with a static subject and have the camera on a tripod, you could measure the distance with a tape instead.

If you're working at or near infinity, this process isn't really a problem because you can pretty much "set it and forget it." But if, for ex&le, you want to do portraits at f:1.4, then setting the focus with the lens wide open becomes a critical issue. Frankly, I'd rather have the 1.4 on an SLR for this, or use a G2 and the 45/2.

My guess--and I've never had any technical confirmation or refutation of this--is that the Gs have been designed from the beginning to work with a maximum aperture of f:2, and that the autofocus system likely isn't accurate enough to reliably work with faster lenses close in.

If there's any question of whether the 45/2 Planar is a good lens, don't worry. I find it outperforms the 50/1.4 (and the slr lens is a very good one indeed). I also haven't found using an f:2 lens to be restricting at all (noting that it's easier to handhold long exposures with a rangefinder than an slr).

--Rick
 

saspencr

Well-Known Member
Thanks Rick. I planned to use it to shoot wide open. My goal was to gain a shallower depth of field than the 45/f2 and also open up more opportunity for low light. Thus, sounds like this is not the way to go. I guess I'll have to start thinking about other options but I do not plan to buy the Leica Ms to gain low light optics as this is too expensive (its a hobby, not a business for me.) Any ideas? I like the G2, its size and abilities. Scott
 
R

rickd

Hi Scott. Do you already own the G2, or are you still considering whether it's right for you before buying?

The 90 could give you the shallow DOF you seek (I sound like Yoda), as well as the foreshortening of a short tele lens and great "bokeh", but not the low-light capability. If bumping up your film speed isn't an option for meager light conditions, then it could be time to consider other systems. FWIW I've got the daring duo of the 50/1.4 and the 85/1.4 and three Contax slr bodies to use them on, but still find I reach for the G2 first.

--Rick
 

saspencr

Well-Known Member
Yep, I have the Contax G2 with the 28mm, 45mm, and the 90mm as well as a Leica Minilux (for pocketability sake). While fairly new to photography, I want to have some "serious fun" and am learning as quickly as I can. To remenice, I did own a Nikon FM2 a long time ago for a few semesters to take the beginning photography class in college and used the Nikkor 50mm 1.4 lens. From what I remember, it was a pretty good outfit. That is long gone now though. Overall I really like the G2 for compactness (stealthiness) and durability and would basically want as close to the G2 as possible except with a faster lens. My favorite aspects of the G2, aside from the quality lenses, are the rugged construction, the ease of the exposure lock, and compensation, and AP mode. It seems that the only things I am missing are spot metering and a fast lens. If I went to an SLR I suspect the quality of the camera would decrease if I wanted something close to the size and features of the G2.

As far as film goes, I am trying out the Fuji NPZ 800 and will see how acceptible it looks, though I like to print at 8x10 and have doubts that it will be as visibly nice as Velvia or Provia 100.

BTW, I uploaded some of my shots from recent trips at
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if you would like to see how my photography is coming along so far.

Thanks, Scott
 
C

cyberstudio

I don't really believe this is going to work. The reasons are as follows:

1, if your camera body shows 1.78m, for ex&le, will you be able to manual focus to exactly 1.78m on your 1,4/50 Planar ? I highly doubt if this is possible.

2, according to my calculations, the rangefinder base of a G2 is not long enough to focus a normal lens at f/1.4 accurately at 0.5m.

I am more interested in mounting a 180mm on a G2 but I am facing the same 2 problems above.

Your main goal is to have shallow depth of field. If you don't care exactly where you are focusing the lens on, then you can ignore the above reasons and just use a GA-1 adapter. However, let's say you are into portraiture and you want sharp eyes but blurred ears/neck/nose, then focusing accuracy is important.

Sticking with the available G lenses the narrowest depth of field is obtained at the closest focusing distances. You will hear a lot of bogus claims about DOF but it basically depends only on magnification and aperture. Magnification in turn depends on focusing distance and focal length, but this also means that a 45mm at 0.5m has the same magnification as a 90mm at 1m. Notice also that blurredness at infinity is a different concept from shallow DOF. You get blurredness at infinity with either a fast aperture or a long focal length (better have both, of course).
 

saspencr

Well-Known Member
Bobby, you write, "also that blurredness at infinity is a different concept from shallow DOF." I understand that a fast lens and/or long lens generally blurrs the background or the areas not in the focal plane. Is it possible to *predict* blurredness at infinity with a DOF scale? Although they are different concepts, are they related? If a DOF scale isn't a good use in determining blurredness, then what might be (aside from experience ;)?

Scott
 
M

mikel

Scott,

I'm not actually sure what you're after, but bokeh always depends on two things - aperture and focal length (angle of view). [ It depends on magnification as well, as Bobby pointed out, but there it's a question of what are you after - that bird 5 feet from you, or that child 50 feet from you. Bokeh is usually nicer when your point of focus is within about first third or half of your normal marked focusing range of your lens. E.g. from 3 feet to 10 feet on Sonnar 85mm f/2.8. If you want nice bokeh - get closer to the object or use longer focal length lens. The effect of bokeh will be different though between what you get on normal lens at 3 feet vs. short tele at 10 feet even at same magnification. For this reason I rarely think about magnification and am more concerned about focal length ]

In my personal opinion, bokeh always looks nicer on normal-to-short-telephoto lenses (from about 50mm to 135mm). Assuming of course we're talking about apertures from 1/4. to about 1/2.8 and no more.

I don't like bokeh on long telephotos, but that's because of the different angle of view (and perspective). And on wide angles it looks nicer than on long telephotos, but isn't quite close to the lenses in the range I listed above.

But then again, it's all a matter of personal taste.

Now, technically you can predict the way bokeh will look on the final photograph. Because as I mentioned, you know the aperture, you know the focal length and you know the distance. And it does come with practice


I'm sure there is a mathematical formula that would descrive the bokeh under different conditions, but personal experience is far more important



Mike.
 

saspencr

Well-Known Member
Mike, thanks for the information. Sounds like you just gave me a new guideline (tool, rule of thumb, whichever one prefers) ... "Bokeh is usually nicer when your point of focus is within about first third or half of your normal marked focusing range of your lens." I'm guessing the focusing range would be the shortest focusing distance through whatever lenght the camera reads for the lens before reading infinity. I don't remember seeing data on the G lenses as to what the last number was. Does anyone have the information handy? Otherwise I'll have to just play with the camera and figure it out. My lenses are the 28, 45, and 90. Thanks again, Scott
 
M

mikel

Scott,

That's exactly why I mentioned "marked focusing range", because I realize that there are no such markings on G-lenses (is there a distance readout in the viewfinder? Never used G-system, so forgive my ignorance).

But you know the minimal focus distance for your lenses, which is already a good start (0.5 meters for 28mm and 45mm and 1m for 90mm).

Technically, since these are 35mm format lenses, unless there is some significant difference in design of G-lenses about which I'm not aware, bokeh would be the same as with similar SLR lenses. So, considering that you have 28,45 and 90, I would say that the best bokeh for the first two will be when your point of focus is in the range of 0.5 meters to about 3 meters, and from 1 meter to about 4 meters with your 90mm.

> I'm guessing the focusing range would be the
> shortest focusing distance through whatever
> lenght the camera reads for the lens before
> reading infinity

Well, let's make it easier.
Taking as an ex&le Sonnar 85mm f/2.8 again (I simply have it in front of me, not because it's so special), the marked range is between slightly less than one meter (about 3 feet) to 15 meters (50 feet) and then infinity. However, when you set your lens at minimal focusing distance, then change focus to say, 3 meters (approx. 10 feet), your focus ring rotation will be almost 180 degrees. But your rotation between 3 meters (10 feet) and 15 meters (50 feet) will be only about 70 degrees (didn't actually measure it, it's my visual estimate). So, the distance on the focusing ring itself will be the longest actually, but the real-life distance will be the shortest of the range for the lens, before it gets to infinity.

So, one third of marked focusing range on Sonnar (15 meters max before infinity) is from 1 meter to 5 meters (16 feet or so). In my previous post I gave an ex&le of 3 feet to 10 feet for this lens only because that's what I personally prefer, but that rough guide of "1/3 of marked range" usually works pretty well. And sometimes one-half is good as well.

Obviously in case of G-lenses it makes it a little more difficult, because you don't actually know the range of the lens. But since in your case you have the same focal lengths as ones available for SLRs, you can use data for SLR lenses as your starting point.

And of course, experiment and find what you like the most - tastes differ. "Diet or regular?"



Mike.
 

keoj

Active Member
I'm think about the GA-1 as well. I would use for experimental (play) purposes only. Original question: anyone used this accessory in real life yet?

Joe
 
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