Yoshizen's Blog

Flower Patch (6) — Canon FD 50mm F1.8 Focus Shift

C'50mm

While a patch of flowers are blooming, I should test the Lenses as many as possible.

C'FD50mmF1.8-F'shift-333-001So, on this post, it was the Canon FD 50 mm F1.8 which was modified to have a motorized

focus.  Funnily enough, the controller of this operation was not that device I’ve designed

for focus-shift but for vibrating a lens.  Despite the battery voltage was low

(nominal 3.7 V battery could give 4.2 V soon after a flesh charge), I found that the

 same device could work for focus-shift as well with some adjustment of the timing.

C'50mm

Unlike the other Lenses of Canon EFS 18~55mm or Tamron &0~300mm, this

50mm lens was worked well on a hand-held shooting, and the pictures’

highlight got pretty smooth halo on them.  = That was what I wanted.

C'FD50mmF1.8-F'shift-3-A09A0420

C'FD50mmF1.8-F'shift-4-A09A0393

C'50mm

C'50mm

C'50mm

The lens was mounted in the plastic barrel which came from a broken Canon

compact camera G9, and with its barrel, the lens can extend to a close-up range

= almost 1/2 size though, unfortunately a blurring halo is an arch enemy of a

macro photography. —– still, some time, the result looks not too bad.  

(See the Bokeh on the blue flower, photo above, (click to enlarge) = they

don’t follow the “Depth of field” ! —– I don’t know how the 5D processed it )

C'50mm

C'50mm

When the lens was re-constructed in the G9’s barrel, I didn’t put the Iris,

therefore this lens is always fully open F1.8 = in this condition, quality of 

the image was rather good.   (You may feel, it’s too funny of me to say that

— Yes, a man after fuzzy image still see an importance of the sharpness)  🙂

[]

Play with Lens

Make Lens-A1-A09A6955

Make Lens-A2-A09A6956

 So far I made quite few lenses to obtain soft-focus or wide-angle pinhole etc,

mostly by utilizing single lens. (still, some of them seemed to be an achromatic

compound lens)  Single lens has inherent aberrations which produces soft image.

Furthermore, I’ve experimented soft images with focus shift or even with camera

shake/vibration using aberration corrected normal lenses. Though, those approaches 

were hardly called technique but more like an opportunist seeking a good luck, since 

the success rate was rather low = lots of try and only few will show the good results. 

That’s because, when the focus ring was rotated while camera’s shutter was open,   

the resulting shake gives devastating effect than a soft nice blur.

= make smooth focus shift while camera was held steadily. = That’s what I need. 

Make Lens-2-300-001

Inside of the Canon G9 compact camera, I found pretty useful mechanism.  

(1) A motor moves the lens.  (2) Small stepping motor shifts a lens for focus.

—– though, those two mechanisms were constructed on the same plastic piece.

(Photo above, left) = I needed to cut and separate its center mechanism out of the

lim with DC motor.  (second photo shows the separated piece = the lim which can

drive a cogged barrel — in the second photo top, the lens was placed in the barrel)  

Photo 3rd and 4th showed the center mechanism — the lens was pushed out most

and pulled inward most by its stepping motor.

Make Lens-3-299-001

The photo above, left is the cogged barrel = when it was rotated by the motor,

the barrel, hence the lens will be extended(= Pushed out) (photo center)  

When motor rotate opposite direction = lens was pulled in. (photo right)

Those function is exactly what I need for a smooth Focus-shift.

Make Lens-1-A09A6852 In order to have an experiment to get a soft focus by the focus-shift ( by a normal

lens, not by the aberration) I took the lens unit out of a Canon 50mm FD lens.  

(Photographic equivalent of gouging the eye !)

( a disc shaped mechanism on the right is the Iris — very useful device )

The lens unit which I’ve put inside of the plastic barrel, in the photo before was this

Canon 50mm F1.8 Lens.  —– though, on the test, I found that this Canon 50mm FD

lens can’t give an infinity focus on Canon EOS = only usable closer than few meters.

(otherwise, the EOS’s mirror will hit the lens bottom.  😦  )

[]

Then, give a thought, what all those hustle for ?

—– Why not just modify a Canon EF 50mm for EOS = 

put an extra electronic connection to override their AF motor !

(Ideally, huck into the Canon camera’s OS and reprogram it to give a focus-shift while

shutter is open = was the best though, not only the risk to destroy the camera but also,

the Canon doesn’t like it at all. ) 

[]

%d bloggers like this: