PentaxForums.com Marketplace Listing Item for Sale
Canon fd 300mm F4L manual focus lens converted to Pentax mount
Asking Price
$225
Item Location
Richmond, British Columbia (Canada)
Item Description Background
I converted this lens to Pentax mount several years ago and used the lens with my K10D and a Pentax 1.4XL extender. At that time, I was frustrated with the selection of Pentax manual focus lenses in the 300mm plus range as my interest was in photographing eagles and song birds. I experimented with a Takumar 300mm f4 lens and a Tokina 400mm SD lens. I hated the long minimum focus distances, the CA and purple fringing, and the need to close down for sharpness. I also had no intention of paying $1000 plus to get the automatic focus lenses with ED or special glass.
The Pentax manual lenses (takumars, k's, M's, A's, even the A*'s) were expensive and had a number of shortcomings: no special glass so the CA and purple fringing were ever present; you had to close the lenses down to f8 or so to get sharpness, and the lenses did not have internal focusing so trying to grab quick focus was difficult. At that time I found the Canon FD line of professional lenses and converted several lenses for use with the Pentax mount.
You can see some of the images that I obtained from this lens and my K10d at
Canon FD 300mm F4 L - manual focus - a set on Flickr. Most shots were taken wide open. I had so much success with this lens that I purchased its big brother, the 300mm f2.8. When I looked at converting the 2.8 lens to the Pentax mount I discovered the micro 4/3 cameras and moved away from Pentax bodies and the need to modify the mounts.
I have not used this lens for a year and would like to pass it to someone who will use it. I recognize that the lens has limited appeal but I also know that this lens will produce outstanding images for a long period of time.
The good news- This lens is sharp wide open with incredible control of CA and purple fringing (special UD glass elements)
- The internal focus design means that you can focus using finger control (smooth and nicely damped)
- Minimum focus is just under 3 metres
- The glass is clear with no fungus
- The lens focuses to just beyond infinity
- You can control the aperture
The bad news- The front lens has minor marks which have no impact on image quality.
- The aperture markings are no longer accurate. The aperture is wide open until it reaches approximately 5.6 and then the readings do not correspond to the actual opening. I wanted the lens used wide open so accepted this compromise during the conversion.
- The previous owner of the lens scratched some letters and numbers in the sliding lens cap and on the barrel in front of the aperture ring.
- The aperture ring is easy to open but is more difficult to close and has friction when closing.
- I am not a machinist and modified the lens mount using hand tools. The K-mount can be removed, I designed the modification this way in case I needed to shim for infinity focus, but it is unlikely that you can return the lens to its original condition.
- There is the usual accumulation of dust inside the lens as befitting its age
The Offering
The lens comes with a fitted tripod mount, the original canon front lens cap, the 1X drop in filter, and a generic pentax rear cap.
Are you the original owner of the item being sold?
No
Are you selling or trading this item?
Selling
Item Condition (Key)
Used
Fair
Shipping Destinations
North America
Shipping Charge
$25
Shipping Services
Canada Post
Accepted Payment Types
PayPal
Return Policy & Additional Details
No returns
Please send me a
private message if interested in the item!
Originally posted by littledrawe 
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