Show us what your adapted lens looks like on your camera

slau

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I think I would put myself in OzRay's corner on this discussion. Although it is feasible to use a longer hood since the effective lens focal length is doubled, the hoods that have been designed for the lens were made to best cover the lenses full front element. It is possible a longer hood could affect the characteristics of the light entering the lens without vignetting occurring, since the purpose of a hood is to eliminate stray light from entering through the front element. If you eliminate the light entering from the lens edges (which would still travel through the center of the lens), it could affect the characteristics of the final image produced - you may not see obvious signs such as vignetting, but the color characteristics (admittedly a subjective, more intangible part of an image!) could also be affected.

Please clarify you above statements a bit. Are you speaking from personal experience/test or just a 'educated guess'? Thanks.

P.s. It will be nice to see an example of a long hood having a negative impact on an image.
 

pxpaulx

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Please clarify you above statements a bit. Are you speaking from personal experience/test or just a 'educated guess'? Thanks.

P.s. It will be nice to see an example of a long hood having a negative impact on an image.

Educated guess, makes sense to me. As I stated it is a completely subjective discussion anyway, I doubt there would be a way to quantify such ideas.
 

pxpaulx

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if you cannot quantify an effect, the effect does not exist.

Really? Quantify good Bokeh for me then. You can't, its subjective! You can only define the word, not what any one person would call good or bad.

I was simply stating that if you think about it, changing the hood on a lens changes the angles (and amount) of light entering the lens element. Although the Angle of view changes on a 4/3 sensor to where a longer hood can be used at a given lens' focal length, limiting the light entering the lens COULD change the rendering of the image to the sensor. Not that it does, not that I have tested it, but that it logically seems possible to me, thats all.

Edit: Sebastel, nice photos in your blog entries. Did you use an m4/3 camera for that IR photo? How long of an exposure was required?
 

sebastel

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i used E-P1 and and hoya R72 for those pics.

concerning effect quantification at the example of bokeh -- i think this is a wonderful example to notice that you need to differentiate between "effect" and "aesthetical quality".

it's rather easy to describe the bokeh effect - it is the "sum" of the light spots, formed by out-of-focus image elements. the actual (blurred) image of each of these elements have a certain shape caused by the distribution of light at the respective image area. it depends on shape of aperture opening, amount and type of aberrations, location of the image area etc (just to mention a few parameters).

now, while the actual _gestalt_ of the bokeh can be described and quantified, this is not the case for its aesthetical reception, which is a matter of taste.

well, this is just my point of view. if you want to disagree, just go ahead. that would be fine with me.

regards
sebastian

edit / add.
of course an extended hood may change the rendering of the image on the sensor. that is the task of such a hood!
the hood is added in order to keep light from the lens that is not intended to be used for forming the image. the problem comes up with imperfections of the lens that may reflect or refract this "out of picture" light in a way that can overlay the intended picture. you usually call this effect stray light or light scatter, or flare.
:)
now for the aesthetical dimension:
if you want to use flare to create your image, you may just leave away the hood, or use one that is smaller than possible.
 

pxpaulx

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I'm no scientist (I will leave that to my wife...as she is one!), but I think I can safely agree with everything you just said sebastel =)
 

sebastel

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sorry for not mentioning before:

the exposure time for the IR pictures was somewhere at 20 to 50 seconds, with apertures 4 .. 8 and ISO 200. you need to try out anyway, so be prepared to take one or two test exposures to see what is required.

the G1 required similar exposure. that means, that the sensor of both is rather insensitive to IR.

a better choice for IR is the epson R-D1. you can even handhold sometimes!
 

pxpaulx

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I'm quite familiar with the expected long exposure times for those shots! Thanks for letting me know what to expect. A couple the older Pentax DSLRs (specifically the *ist series of cameras with 6mp sensors, probably about 4 years discontinued) had quite a weak IR cut filter. You could shoot at about 1/30 of a second handheld with them. The newer models had stronger filters, requiring the requisite long exposures (15 seconds+). I had been using an ebay cheap IR filter, but thought it was more just a deep red, and received a hoya r72 for Christmas (52mm for one of my kit lenses). Of course everything is covered in snow here, so it will be awhile before I can put it to use!
 

sebastel

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:-D

i know where you are at. i just received a (special offer) B+W 092 (39mm, perfect match for my preferred 25mm snapshot skopar), and i find new cursewords for the current weather every day.

by the way, the *ist sensor should be almost the same like the one in the epson, and nikon D50/70/70s.
the epson is extremely good for IR, because the finder does not "see" the IR filter ... (the leica M8 should be even better, but not in my price range yet)
 

BillN

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G1 from 2010 with leica lens from 1933

Should be interesting - got the adapter this morning

The lens is a Leica Elmar 50mm f3.5 (LTM) from 1933 which, I think was the first year of production.

The lens looks coated but I do not think that is was originally - but if it is there are a few "patches" on the front element

I took a couple of "quick and dirty" images and all looks OK - will post a few images in due course

DO NOT COLLAPSE - DO NOT COLLAPSE

G1_Elmar_Screw.jpg
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[/url][/IMG]
 

jesse

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G1 with Leica R 400mm f6.8
G1R400.jpg
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jesse

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G1 with Leica M50 f1.0
G1Noctilux.jpg
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jesse

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G1 with Leica bellow and M90 f2.8 Elmarit
G1Bellow.jpg
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jesse

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G1 with Alpa 50mm Macro Switar
G1MacroSwitar.jpg
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OzRay

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That 50mm f1 looks smaller than my Voigtlander 50m f1.1. I've also got a Zeiss Icon bellows which I'm in the process of modifying so that the camera bayonet is a Leica fit and the lens bayonet a m4/3s. This worked out to be the easiest way to convert things.

Cheers

Ray
 

BillN

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Jesse

post some shots with the Alpa and the f1.0

Those Alpa lenses must be like "gold dust"
 

BillN

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nice!

metallic red - I once had a Merc that colour!

we aught to have a competition for the best looking combo!

This one is interesting

picture.php
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