Problems with 4/3 fast lens on m4/3 camera

[toshie]

Hey guys,

Not sure if you guys had meet with this problem. My friend had bought a nikon f1.4 lens to fit it to his m4/3 camera(gf1).

However, we notice that at f1.4 wide open, the image is never sharp(Manual focus). It seems that the colour "spills out" of the edges and photos looked dreamy effect(Is this what you guys called color bleeding or over spilled?) The "color spill" got worst at the whites. My guess might be too much light reaching the sensor maybe(over contrast)? The problem can only be solved when we close the aperture to f2.

I was planning to buy a f1.2 four thirds lens on my gf1 too but now I have to reconsider. Unless there is a solution to solve this problems.

Thanks for any advise!

 

[spidey89]

My guess is that its the characteristic of the lens, most lenses are not sharp wide open and requires to be stopped down. My guess is that but I could be wrong

 

[Agrivar]

Nikon legacy lenses are not 4/3 lenses. 4/3 lenses are made for 4/3 DSLRs from Olympus (E-1, E-2, E-3, E-30, E-4XX, E5XX, E620 etc) and Panasonic Mirrorred DSLRs (LC10 LC1) and not the mirrrorless m4/3 cameras (oly PEN Epl1/epl2, Ep1/Ep2 or Panny Lumix G1, G2, G10, G3, GH1, GH2, GF1, GF2).

Most legacy lenses can be adapted to m4/3 cameras via an adapter. But most legacy lenses are not made for Digial sensors and hence the design of the lens elements capture and diffract light differently. Hence its not surprising that your friend's nikon legacy lens needs to be stopped down to achieve adequate results.

The only native bright m4/3 lens is the Voightlander 25mm/f0.95 MF lens by Cosina. That is quite sharp wide open, but even then gets sharper by f1.4 or so.. you might want to consider this lens..(this is native m4/3 mount and is made for m4/3.. so not a legacy lens) :bsmilie:

Other lens alternatives can be read here :
http://www.mu-43.com/f40/nikkor-50mm-f-1-2-useful-mft-other-f-1-2-lenses-8769/

Do some searching for legacy lenses on mft / m4/3 on google. Lots of posts and articles. But the general premise is that you need to stop down the aperture of legacy lenses to achieve sharpness.

 

[spidey89]

What about 20mm f1.7? Orh hor!!!! XD

 

[Agrivar]

What about 20mm f1.7? Orh hor!!!! XD

20mm is not a legacy lens mah.. quite sharp at 1.7 or even 2.0

 

[wwooaahh]

Hey guys,

Not sure if you guys had meet with this problem. My friend had bought a nikon f1.4 lens to fit it to his m4/3 camera(gf1).

However, we notice that at f1.4 wide open, the image is never sharp(Manual focus). It seems that the colour "spills out" of the edges and photos looked dreamy effect(Is this what you guys called color bleeding or over spilled?) The "color spill" got worst at the whites. My guess might be too much light reaching the sensor maybe(over contrast)? The problem can only be solved when we close the aperture to f2.

I was planning to buy a f1.2 four thirds lens on my gf1 too but now I have to reconsider. Unless there is a solution to solve this problems.

Thanks for any advise!

I believe this effect is called "ghosting", due to internal reflection between the sensor and the back element. Old lens does not have coating to reduce this reflection, because it was used on film which does not have that much reflection.

 

[spidey89]

The Voightlander is legacy?

 

[Agrivar]

The Voightlander is legacy?

New.. : ) but MF

 

[spidey89]

hahahah

 

[sci80312]

Hi,

I believe that dreamy look is the characteristics of that lens. Most fast prime are never sharp wide open and contrast usually tend to be lower compared to when you stopped down. What you described sounded like spherical aberrations of the lens resulting in softness of the pictures. Softness at wide open could be a highly desirable characteristic depending on what you shoot. For portraits and baby shots, this lens could probably shine. FYI.....soft portrait lens could be very expensive. If you dun want the softness, just stop down and you are ready to go.

 

[toshie]

Hi,

I believe that dreamy look is the characteristics of that lens. Most fast prime are never sharp wide open and contrast usually tend to be lower compared to when you stopped down. What you described sounded like spherical aberrations of the lens resulting in softness of the pictures. Softness at wide open could be a highly desirable characteristic depending on what you shoot. For portraits and baby shots, this lens could probably shine. FYI.....soft portrait lens could be very expensive. If you dun want the softness, just stop down and you are ready to go.

Oh, you made me start to appreciate it. Haha~

 

[toshie]

Nikon legacy lenses are not 4/3 lenses. 4/3 lenses are made for 4/3 DSLRs from Olympus (E-1, E-2, E-3, E-30, E-4XX, E5XX, E620 etc) and Panasonic Mirrorred DSLRs (LC10 LC1) and not the mirrrorless m4/3 cameras (oly PEN Epl1/epl2, Ep1/Ep2 or Panny Lumix G1, G2, G10, G3, GH1, GH2, GF1, GF2).

Most legacy lenses can be adapted to m4/3 cameras via an adapter. But most legacy lenses are not made for Digial sensors and hence the design of the lens elements capture and diffract light differently. Hence its not surprising that your friend's nikon legacy lens needs to be stopped down to achieve adequate results.

The only native bright m4/3 lens is the Voightlander 25mm/f0.95 MF lens by Cosina. That is quite sharp wide open, but even then gets sharper by f1.4 or so.. you might want to consider this lens..(this is native m4/3 mount and is made for m4/3.. so not a legacy lens) :bsmilie:

Other lens alternatives can be read here :
http://www.mu-43.com/f40/nikkor-50mm-f-1-2-useful-mft-other-f-1-2-lenses-8769/

Do some searching for legacy lenses on mft / m4/3 on google. Lots of posts and articles. But the general premise is that you need to stop down the aperture of legacy lenses to achieve sharpness.

Hey thanks man~ I'll look up more info online. Voightlander 25mm/f0.95 can really blow a big hole in my pocket, using these prime lenses are of much cheaper choice to me. Haha~

 

[toshie]

Hey guys,

Correct me if I am wrong. I seems to find out that lenses like nikon although stated aperture f1.4, when used with m3/4 camera may be operating somewhere like f1.0 of m4/3 equivalent!

Reason behind it:
Lenses like nikon for example f1.4, the aperture is built with respect to their camera sensor size(which is larger then m4/3). So if it is fixed to m4/3, the aperture opening is much bigger then m4/3's f1.4.
I actually took a sigma zoom lens at f3.5 to compare with my gf1 zoom lens at f3.5. The aperture opening difference is HUGe!

LOL.

 

[Agrivar]

Hey guys,

Correct me if I am wrong. I seems to find out that lenses like nikon although stated aperture f1.4, when used with m3/4 camera may be operating somewhere like f1.0 of m4/3 equivalent!

Reason behind it:
Lenses like nikon for example f1.4, the aperture is built with respect to their camera sensor size(which is larger then m4/3). So if it is fixed to m4/3, the aperture opening is much bigger then m4/3's f1.4.
I actually took a sigma zoom lens at f3.5 to compare with my gf1 zoom lens at f3.5. The aperture opening difference is HUGe!

LOL.

Sorry. That reasoning is incorrect. Aperture is the same across all types of camera formats. So an f1.4 on m4/3 is the same on aps-c and same with Full frame. What may be different is the corresponding FOV ( field of vision ) due to crop factor and arguably even DOF ( depth of field ).

The physical size of the lens opening has no direct relation to aperture. I.e. A lens with bigger opening doesn't have bigger aperture than another lens with smaller opening. It is measured in relation to the FL.

"The lens aperture is usually specified as an f-number, the ratio of focal length to effective aperture diameter. A lens typically has a set of marked "f-stops" that the f-number can be set to. A lower f-number denotes a greater aperture opening which allows more light to reach the film or image sensor. The photography term "one f-stop" refers to a factor of √2 (approx. 1.41) change in f-number, which in turn corresponds to a factor of 2 change in light intensity."

- wikipedia
http://en.wikipedia.org/wiki/Aperture
http://en.wikipedia.org/wiki/F-number

 

[spidey89]

Sorry. That reasoning is incorrect. Aperture is the same across all types of camera formats. So an f1.4 on m4/3 is the same on aps-c and same with Full frame. What may be different is the corresponding FOV ( field of vision ) due to crop factor and arguably even DOF ( depth of field ).

The physical size of the lens opening has no direct relation to aperture. I.e. A lens with bigger opening doesn't have bigger aperture than another lens with smaller opening. It is measured in relation to the FL.

"The lens aperture is usually specified as an f-number, the ratio of focal length to effective aperture diameter. A lens typically has a set of marked "f-stops" that the f-number can be set to. A lower f-number denotes a greater aperture opening which allows more light to reach the film or image sensor. The photography term "one f-stop" refers to a factor of √2 (approx. 1.41) change in f-number, which in turn corresponds to a factor of 2 change in light intensity."

- wikipedia
http://en.wikipedia.org/wiki/Aperture
http://en.wikipedia.org/wiki/F-number

Confusing hahahah, but I guess in a nutshell, the aperture size is based on a complicated mathematical calculation that I can understand, which is unique for each lens and doesn't change no matter what the medium is, its like, rotten milk will still be rotten milk whether you place it in a golden...errmmm... liquid dispenser thingy or in an old milk carton that is obviously very worn out

Seriously, all my examples are lame, regardless, properties of the lens itself remain the same, the end results produced are different depending on the medium used, like for example, a lens made for film works great on film cameras, but it need not necessarily be good on the digital sensor

 

[elgkh]

One way to reduce the dreamy look is to make the rear aperture smaller, by covering it with a piece of cardboard. Look up "light baffle" or "lens baffle" for more. I have not tried it myself though.

The softness wide open is normal for lenses with larger apertures than F2.

 

[toshie]

Sorry. That reasoning is incorrect. Aperture is the same across all types of camera formats. So an f1.4 on m4/3 is the same on aps-c and same with Full frame. What may be different is the corresponding FOV ( field of vision ) due to crop factor and arguably even DOF ( depth of field ).

The physical size of the lens opening has no direct relation to aperture. I.e. A lens with bigger opening doesn't have bigger aperture than another lens with smaller opening. It is measured in relation to the FL.

"The lens aperture is usually specified as an f-number, the ratio of focal length to effective aperture diameter. A lens typically has a set of marked "f-stops" that the f-number can be set to. A lower f-number denotes a greater aperture opening which allows more light to reach the film or image sensor. The photography term "one f-stop" refers to a factor of √2 (approx. 1.41) change in f-number, which in turn corresponds to a factor of 2 change in light intensity." r

God.... sooo chim... But basically u mean that all lens will perform the same no matter what body is use right? Just that different lens are optimized to different sensors....

 

[toshie]

One way to reduce the dreamy look is to make the rear aperture smaller, by covering it with a piece of cardboard. Look up "light baffle" or "lens baffle" for more. I have not tried it myself though.

The softness wide open is normal for lenses with larger apertures than F2.

That was useful bro! I will look up for more information now~ Thanks!