Jonathan's blog

In 1987, Canon introduced their new autofocus-capable EF lens mount for their EOS series of cameras – including today’s digital SLRs. It was incompatible with the older manual focus FD lens mount. The flange focal distance of the newer EF lenses is slightly longer meaning that an adapter for mounting FD lenses on an EF body must contain an optic to allow infinity focusing. This immediately means the image quality will be affected by the adapter. But to what extent?

I bought a Kood adapter (although there are many, many brands available) to use my FD lenses on my EF-mount EOS 450D camera. For £15, I thought it would be a fun way of getting some extra use out of my FD lenses, even if the quality wasn’t great.

Kood FD-EF adapter

The competitors

I decided to do a side-by-side comparison of my Canon 50mm f/1.8 lenses – FD and EF mount respectively. I shot at ISO400, 1/60s, f/4 with flash. (Perhaps some other time I will think of this experiment when it’s not dark, and try it in daylight.) The camera was on a tripod.  I used autofocus and centre-weighted program exposure with the EF lens. I used the same shutter and aperture settings for the FD lens, and focused manually using live view, magnified to 10× in on the LCD.

Canon FD 50mm

Canon EF 50mm

Results

For a start, you might notice that the FD lens is slightly more zoomed-in than the EF lens. This is a side-effect of the correction optic to allow infinity focus. I’ll show both photos here, including 100% crops at 1024×768. Click the images to view them at this size. Other than cropping, no sharpening or any other editing has been done on these images.

EF lens	FD lens
EF lens	FD lens
EF lens (100% crop)	FD lens (100% crop)

I am honestly staggered by these results – the sharpness of the FD lens is much better than that of the EF lens. It’s possible that the autofocus didn’t do its job properly but it does prove that this third-party FD-EF mount adapter isn’t so terrible. I can only speak for mine – I’m sure there are terrible ones out there.

Pitfalls

There are some other things to be aware of though. Obviously the FD lenses don’t support autofocus, so you have to focus manually. This is no problem on a genuine manual focus SLR body, but autofocus SLRs lack the split-circle and microprisms on the focus screen, so it’s a lot harder to focus using the viewfinder. Using live view is a workaround, and it is also possible to swap out the focus screen for one with a split-circle, microprisms, or both.

While FD lenses do support an aperture controlled by an FD body, it won’t work using an adapter like this. You will need to take your meter reading using any appropriate method, and then set the aperture – this is stopped-down metering. The viewfinder will darken when the aperture is stopped down. This particular Kood adapter has a switch to flick between fully open and stopped down, which helps.

Summary

But if you are in the same position as me, with an EOS SLR and a load of FD lenses, I don’t think you’ll regret spending a few quid to be able to use them on your digital body. The quality, at least of this Kood adapter, is perfectly good – perhaps flawless.

Update

As promised, I have now added some outdoor photos taken from my window. I slightly cropped the zoomed-out version this time, to give a comparable field of view. I’ve taken a 100% crop of the unaltered original to test edge sharpness.

Both photos were taken at ISO100 and f/5.6, but the EF version was taken at 1/50 and the FD version at 1/40 as the darkness was coming in. Both are a little underexposed, I think, due to the pale sky. and the FD version is a little darker.

EF lens	FD lens
EF lens	FD lens
EF lens (100% crop)	FD lens (100% crop)

On this occasion, the autofocus seems to have got it spot-on and my manual focusing isn’t quite perfect. Image sharpness otherwise seems good, especially towards the edge of the photo where you might expect softness,  and I can’t see any chromatic aberration around the chimney.

The real test will probably be using this lens in strong sunlight – which I shall try to find the time to do at the weekend.

Back in September 2009, I was given a 35mm SLR camera – a Canon AE-1 Program. I loved it, it was fantastic to use, and I wrote a blog post about the possibility of upgrading to a DSLR.

In March 2010, temptation got the better of me and I bought a Canon EOS 450D. My main concerns beforehand was the loss of the large LCD viewfinder of my Fuji S9600, and in particular, not being able to flip it out for awkward shots, and not being able to see useful information about the camera settings in the eyepiece.

Well I needn’t have worried – the 450D is of course more advanced than my AE-1 and has a small LCD under the optical viewfinder for that information. I hadn’t realised until I tried it out in the shop.

The issue of having to put my eye up to the camera still hasn’t been addressed, but it hasn’t been a problem. I just find myself lying on my belly more, or simply pressing the button and guessing about the composition.

In the two months that I’ve owned the 450D, I’ve taken over 2,000 photos^[1] and I’ve thoroughly enjoyed all of them. I feel more in control of the photos, and I can’t recommend an SLR strongly enough to anyone who is serious about photography.

I now have three EF mount lenses for this camera. Unfortunately they don’t fit the AE-1 (which uses the FD mount) but this very evening I bought a Canon EOS 300, which is a consumer-level 35mm SLR with an EF mount. You can pick up 35mm camera bodies on eBay for a fiver so I thought it might be nice to make even better use of my lenses.

If you’re actually interested in any of my camera facts and figures, you might like to look at my page of cameras. If you’re more interested in the pictures themselves, then why not browse my photo blog.

[1] That’s about 1.4 each hour I’ve owned the camera