Monday, January 28, 2008

Review: Bower EOS/FD Converter

After my impulse buy of a Sigma 600mm in a Canon FD mount, I had to scramble to get an EOS/EF-FD adapter that would let me put it on my Canon 20D. eBay has a number of adapters to choose from, but I went with a Bower/Hartblei adapter from HartbleiOptic. The same product is sold by a number of sellers online. The seller seems to have a strong Russian/Ukrainian connection (both the e-mail address and the fact another seller was using identical listings (based out of New York with Kiev in the name)). That made me a little nervous (not the Russian thing, the identical listing thing) but their service was great, shipping fast, and I have no complaints. I highly recommend HartbleiOptic as a seller, (edit: HartbleiOptic is no longer an eBay seller (suspicious!) but the Bower converters are still available). An eBay search is below:

Total cost (including shipping) was $36, which was the lowest I could find for the given adapter. From the pictures, there were a number of eBay suppliers with the same item. It was very important to me to get an adapter with a removeable correction lens so that I could improve image quality at the expense of infinity focus. To help you identify the adapter, I included the box in the image below; note the adapter is marked Hartblei and the box is marked Bower. Bower is a well-known low-end Japanese manufacturer of photographic lens accessories. Hartblei is a German company (I think) specializing in medium format tilt-shift lenses and accessories.
For the record, the adapter comes with NO DOCUMENTATION, so I had to figure out everything through trial and error.

Physical Characteristics:

The adapter came inside the box wrapped in plastic with the correction lens installed. The box also includes two caps (the EOS cap is nice, the FD cap is little more than a rubber sheath and quite cheap). I was very surprised at the quality of the machining -- everything seems high precision which is a surprise this day in age. Also, the whole adapter is covered with matte black paint (powder coating?) which seems pretty durable. The lens is obviously coated, although I can't imagine it is the best quality lens given the price.

The adapter itself seems extremely sturdy and is entirely made out of metal. Placing it between the camera and lens I noticed no flex or give at all, with the exception of the outer aperture control ring. The outer ring seemed to flex a little when I squeezed it hard at one point, but didn't get damaged. As long as you aren't super hard on it, I can imagine this item will last a long time. The aperture ring has a nice click to it too.


Obviously, the goal of this adapter is to attach on one end to an FD breech lock mount lens and the other end to an EOS camera body with an EF mount (FYI, EOS is the camera system; EF is the mount). In the next post I'll cover why you might want to do this; in this post I'll focus on the review of the converter.

When attached between my Sigma 600mm f/8 Mirror and my 20D, the converter worked admirably -- no slop and very sturdy. As it should be. It doesn't really have many moving parts because it doesn't really need them.
The main moving part is the aperture ring, which, as far as I can tell, is used to manually trigger the aperture lever and switch between the lens's stopped down setting and the fully-open setting. This could be very useful for acquiring focus wide-open, then stopping down at the last minute to shoot. Whether it will be convenient to use remains to be seen, since I am unable to test it (the Sigma 600mm has a fixed aperture). I'm also not wild about the screw being silver (since the screw will be on the lens side there may be internal reflections), but it should be an easy thing to pick up a black screw at a hardware store and replace it. The screw and the ring (marked Lock/Open) are easily seen in the image above.

The other moving part of the adapter is the internal lens element, which unscrews for removal as shown below. Again, since I didn't have instructions, I had to figure this out on my own. Be careful as you remove the lens, because you could slice your fingers on the threads (it is a bit tight from the factory). There are some indentations which may be used to loosen it with a screwdriver, but I don't recommend it because you could scratch the matte finish. Rubber gloves might help protect your fingers and maintain your grip.

Once removed, the adapter acts like a small extension tube, increasing magnification (and bring the focusing distance closer so you can't focus the lens at infinity). Since I don't need infinity focus (for most purposes I've got other, better lenses for that) I'll probably keep it out most of the time. And, as extension tubes go, it should work great, since it has an internal wall to block some of the light.

I'll talk more about performance in the Sigma 600mm review, including a comparison between using the adapter with the lens and without it. I'm very curious how much the lens reduces resolution of images. My hypothesis is that it is significant, but I'd love to be surprised.


If you decide/need to use older FD lenses, I think this converter is an excellent deal. It has great workmanship, can be used both with or without the correction lens, and has everything I could ask for. I highly recommend it!


Sean said...

(Jack's post, minus his e-mail address):

I have the EOS 30D and I have just purchased the Sigma600 FD. (Haven’t got it yet)
Have you ever considered to disassemble the FD mount and to make a special EF mount for the Sigma600?
Is it possible to disassemble the FD mount?
I am a mechanical engineer and I am thinking to do so. (Looks like a nice project)
Please send your opinion.

Sean said...

(my response)

You can kind of get an idea of what you are up against based on some of the images in my Sigma Review. It appears the mount can be disassembled, but I have never tried it. I looked at mine and it has three small screws on the FD mount, leading me to believe you can take it right off.

If you are pretty good at machining, you could probably make a new base mount and save the old one if you wanted to return it to stock condition. If you are willing to destroy the FD mount, you can probably do it even easier.

EOS Sigma 600mms are available, but very rare, and tend to command a higher price on eBay. Even with the modified mount you may not be able to get true infinity focus (as designed) but you could probably get pretty darn close. The main problem is the FD focal distance is shorter than the EOS, making it hard to get a true match.

Ajay said...

Can you share some pics that you took using this converter. Am stuck with a Sigma 600mm FD mount (ebay seller mentioned wrong mount) and it requires international shipping to return the same. If the results using this adapter are "acceptable" might as well keep the lens.

Sean said...

I've used the converter with my Sigma 600mm with some pretty good results. BUT... I never use it with the glass element in (unless I'm shooting something very far away) and the main limitation is the 600mm lens itself.

Details with sample shots are all under the Sigma600mm label.

Anonymous said...

Sean, Thank you for your response. Assuming that you have something to shoot far away- a moon perhaps, or some bird or whatever, are the pictures usable inspite of the optics that the adapter contains.

Usable not in terms of selling the pictures, but atleast in terms of displaying on your website and not getting a comment- "gosh! looks like u used a crap lens"

Ajay said...

"Details with sample shots are all under the Sigma600mm label."

Oops, I missed that. All the bird shots are with using the adapter i presume. including the duck shots...

Sean said...

With or without the corrective lens in the adapter, I'd say the shots are usable for web-resolution. Probably usable up to 5 x 7 inch prints without the adapter as long as you nail the focus and have a high shutter speed.

Almost all the shots in the Sigma600 label are shot with the Sigma (the night heron is my Canon 70-200mm f/4 though). Actually, all but the moon shots (and possibly one or two others) DO NOT use the corrective optics. I've found I can focus without the corrective optics up to 1/4 of a mile or something like that -- in other words, most of the time I don't need it. The moon shots definitely do use it though.

biping said...

Dear Sean, yours was the very best write up on a mirror lens. There is a seller on Craigslist Toronto who has the Sigma 600/8 Mirror Lens in Pentax K-mount for sale. Request your help & advise:-
1) can I go ahead and buy this lens for CAD 75? he does not have the lens hard case + the (4) filter set. The lens hood + front/rear lens caps are available. Claims it is fungus free.
2) one post on the net says that there is a normal filter for this mirror lens and it has to be permanently left in place inside the rear of the lens. Here is the exact quote, "Sigma has a clear filter to be used at all times unless you needed to use the ND to cut the light down. The lens goes to hell without that extra element in line".
3) the filter dia is very confusing. One spec says 30.5 mm while another says 22.5 mm. A 30.5mm set is on sale for US $ 12 on ebay and I wanted to pick it up.
4) another thread says, "Always use a UV filter because the lens has very little glass to absorb UV. 95mm filters are expensive and hard to find. Try the rear filter system on this lens". Is this true?
5) this lens has to be used in the "M or Av" mode I suppose. Which do you recommend and any practical advice?
6) Mirror lenses are very easy to knock out of alignment. Underneath the central obstruction there is usually a way to adjust this by turning 3 screws. This must be done on a stable tripod. Point it at a star or bright distant light and adjust until it is a round point. This is a slow process. It is amazing how just barely touching the screws makes a difference.
Is it necessary and do you recommend it?
7) are there any other pertinent points, since you had mastery over this lens.
I have read your detailed report but please forgive me if I have repeated some questions. I am old and tend to forget things easily.
Thanks & Regards.
Bipin B. Gupta
ex Advisor Nissan ME, North Africa & the CIS

Sean said...

Sorry for the delay in the reply -- this one got lost in my inbox... Here are the answers to your questions; I hope it isn't too late!

1) The price for the lens seems decent, but the K-mount may or may not change the value (and I'm not sure if it does).

2) I never found an issue without that element. In fact, I always left the clear filter out because I didn't want any extra glass in the optical path if I didn't need it. There may be an increased risk of dust in the lens if you have it out though.

3) See above. I'd wait on the filter set before you get the lens. And, quite honestly, unless you shoot film I wouldn't bother with the filters.

4) I never use UV filters, but I also shoot a lot of digital with lenses that have coatings designed for digital. If you shoot a lot of film outdoors at long distances, you might want a UV filter, and then, yes, I would go with the rear filter (the front filter would be huge and expensive). Actually, a UV filter might be nice since the lens is usually used at long range, but I'd wait until you've used the lens a bit before you make the decision.

5) Av mode is generally what I shot it in. Sometimes M if I new the exposure (typically the sun) was consistent and the internal meter might get tricked by a dark or light subject. After all, you are going to be VERY zoomed in.

6) I never adjusted my lens, so I can't give any advice. Sorry! (generally, though, don't mess with it unless you have a need to)

7) This lens is all about technique (using a good monopod/tripod with a fast shutter and a good firm hold). The donut-shaped bokeh is very distinctive and often distracting, so you'll want a clean background as much as possible. Also, the natural limitations of the lens in sharpness will cause soft images on cropped frame digital -- I'd more readily recommend it for film or full-frame digital (but if you can afford a full-frame digital camera, there are probably better lenses out there for you!)

Let me know if you have more questions,


Anonymous said...

How do I remove this adapter from my 55 1.2 lens? I think it's a piece of junk, and now I can't get it off. Help!!!!!!

Sean said...

This adapter doesn't have a button on it, but the newer FD lenses did. You may just have to rotate it relatively hard -- or try pushing and twisting like a pill bottle. Just be gentle but firm and try different motions. If that doesn't work, stop by a local camera shop and see if they have ideas...