Saturday, 27 June 2009

RJ Camera FD adaptor

Bottom line first:

This adaptor is cheap and will get your lens onto your camera, but its mechanically flimsy and the multi part construction with poor quality screws leading to issues with accurate alignment are the weak points. If you value adapter accuracy, reliable build and high quality then look to the ciecio7 (a polish eBay seller) adapter on eBay. I have been using his for some time now and they are machined from a single billet of alloy. They are robust and reliable and very well priced. note: I have nothing to do with ciecio7, I just like his gear. See my views on the free market Invisible Hand.

He has been iteratively developing them for some time and you can find my posts on those adapters here. At the time of writing this blog post I was initially quite unable to say what I wanted without an amount of whinge from the Chinese ebay seller. As this post is still popular I thought I'd add this 'prelude'. The rest remains as it always has been.

I've been using a few FD lenses on my G1 and been reasonably happy with the adaptor that I have been using. You can read about that adaptor here.

There were a few issues I had with that adaptor and how it fitted onto the lens as well I had felt that it would be nice to have an adaptor which allowed me open and close the aperture iris without needing to fiddle with the lens aperture ring.

Someone wrote to me suggesting that jinfinances adaptor (the adaptor shown here) had exactly this in his latest model.

I asked jinfinance (the eBay seller) and he seemed not to be sure if it did or if it did not, however he was kind enough to lend me one for me to review on my blog and to answer my question.

So, the answer is yes it does. The adaptor has some interesting features which I'll describe.

The physical:

If you look carefully at the above image you can see a groove which allows the lens iris operation coupling pin to move. Its operated by grasping the grip ring just behind the lens mount and turning it a few degrees. This is perhaps also visible in the image below.

and in close up

This then operates the mechanical stop down lever on the lens to close the aperture to the size you've set on the lens aperture control.

Why would you want to do this? Well it does make it easier to focus with the lens wide open (especially if its dim) and its also easier to pick exactly where critical focus is with the lens fully open too.Since I've been using an adaptor without this feature for some time I was keen to see if it would make a significant difference in operation.

As I've been using OM lenses I have essentially had the same operation by removing the coupling pin from the adaptor and using the Depth of Field preview button that is standard on the OM lenses. This has shown me that sometimes its handy, and sometimes its not. Particularly I find that when working on a tripod photographing birds at a nest, or when trying to follow focus small ducklings that its not. Either I'm trying not to shake the camera or just too occupied with othe controls.

When working with photographing people with mid range lenses its handy. However with the FD lens (unlike the OM lens) and on this adaptor I need to rotate a ring rather than press a button. In this case I found that it is not as neat a method and gets in the way of foucs and operation.

The reason for this partly due to the ring being so close to the aperture, partly due to the ring being stiff to turn, and partly due to it being all quite cramped in there.

This image shows a couple of things; firstly don't snack on oily chips when handling a matte black camera for photography.

Ahem ... well anyway, the already snug space between the grip and the lens is taken up a bit more by the adaptor. Personally I can get my fingers in there, but I'm sure what the people who complain that the camera is tiny (NB with big fingers) may have a different report. As readers of my blog may recall, I already have an adaptor from Ciecio7 , looking at that adaptor you can see the difference between the two.

maybe its easier to see this when morphing from one adaptor to another


Essentially the RJ adaptor is wider than the base of the lens and its a little bulkier.

There is one last important point in the physical, that is concerning mounting the adaptor and engaging the aperture diaphragm or iris when you mount the lens on the adaptor.

The RJ adaptor gets around a problem which seems to afflict all of the other FD lens adaptors, by having the rotating ring around the outside to engage and disengage the iris control this adaptor gets around the problem of needing to engage the FD iris coupler during the mounting process and the iris coupling is engaged by turning the ring after mounting.

To mount the adaptor and then engage the iris coupler you there is a green dot (visible on the first picture), line this up with the red dot on the chrome part and also red dot lens. Then mount and turn the lens normally. The iris is then engaged and stopped down by turning the ring on the outside of the adaptor (which moves the engaging pin as in the diagram above).

One of the things I've notice with the other adaptor (and indeed this one if you don't decouple before dismounting) that some of my FD lenses are a bit difficult to unmount. In particular when using extension tubes this is quite important, as I can't take my lens off and add a tube without using this system.

This means that with the RJ Camera adaptor and using macro extension tubes I can start with an extension tube which I think is about right (but perhaps a little short) and I can then add another tube without taking it all apart. By decoupling the iris, I can simply remove the lens (leaving extension tube and adaptor on the camera) add another few mm of extension tube onto my stack and put the lens back on. This can be a pain, but lately I've been getting pretty good at guessing first hit what extension I need. This makes me wonder if the design is intended to give aperture operation or simplify mounting?

Either way this ability to couple and uncouple the iris provides macro and extension tube users with a significant benefit.

So from the physical side:
  • its well made,
  • looks great has,
  • gives manual control over the aperture and
  • is easier to mount and dismount a the lens

Infinity Focus

To test this on this adaptor I used my FD 28mm lens, as the shorter focal lengths are more sensitive to the precision of the adaptor length than longer focal lenghts are. What I found was that with the lens wide open that the RJ adaptor is a little short of infinity. The bottom image is the RJ and the top is the Ciecio7 adaptor...

Its not huge, but the RJ adaptor is not reaching infinity. When I first got the Adaptor from Ciecio7 I found that it too was not focusing at infinity, and I found that the solution to this was to lap down the front surface. Given that design was a single piece of alloy turned down the right shape, it made sence to simply hone down the front surface. However with this lens I'm not sure if I'd like to do that.


I like both these adaptors. I'd be tempted to modify the RJ adaptor to bring in infinity focus. Having discussed previously my thoughts on the adaptor and infinity focus issues I don't think its a significant issue. Certainly by f8 you can't really pick much difference. Is it significant to you? Well I guess it depends on how much you take landscape images of infinity using f2.8

I thought I'd leave you with a side by side of the two adaptors. To me the RJ adaptor is s very nice looking piece of gear that does the job, provides nicer mounting and un-mounting and the ability to open and close the iris for focus and taking with out moving your aperture ring. The Ciecio7 adaptor is more simple both in looks and operation, but then its also cheaper and does the job just as well. Both need some honing to have them infinity focus perfectly.

In my view the Ciecio7 is great value for money (being cheaper), is simply and solidly made and gives me more room for my fingers between the lens ang the grip. The RJ adaptor has the bonus of being able to engage and dis-engage the aperture coupling during mounting (making some things easier as mentioned above) and allows you to open and close the aperture without changing its settings (should that be important to you)

The rest is your call :-)

post scriptum: infinity focus revisited - problem solved

I received an email from RJ Camera asking me to check that the adaptor plate was properly torqued down and asking me to check again the infinity focus.

He felt that this may make the difference. It is after all only small fractions of a mm we're talking about so I pulled out my jewelers screwdriver and found that I could indeed torque it down about 1/3 to 1/2 a turn on each of the three screws.

I then put on the lens and took another shot ... sure, the lighting has changed, but this is now compared to the image from the Ciecio7 adaptor (the top one in the previous comparison) and its more or less identical. Here is a 100% pixel view:

So, this means that before you get concerned about your infinity focus, to check that all the screws are properly tightened.

But I advise you to be quite careful in doing this.

  • Do not apply too much pressure on your screwdriver or you may strip the thread (it is into aluminum after all)
  • use a proper sized screwdriver (most hardware stores and many supermarkets sell a small set for less than $10)
Once you are happy with focus, I would recommend putting the smallest amount of some kind of thread lock cement on them to prevent them from vibrating loose in future. Perhaps it is something which the manufacturer could consider?



Matze said...

Very nice and in depth review. Thanks for posting. I own the RJ adapter and will check the screws now, thank for the hint.

rawmeyn said...


I have a GH1, the RJ Camera FD Adaptor and two FD Lenses (50/f1,4 & 24/f2). I can mount the lenses on the camera without a problem. BUT: It seems that the Aperture is not working right. I just can´t open it all as far as it should. On the 50mm I get the same aperture at f1.4 as a f4. And on the 24mm i can´t get lower than f5.6. What´s wrong here? I did a google search and found those two posts:

So I did exactly that and everything works fine when I test the aperture with the unmounted lens. BUT: Now I cannot mount the lens with the adapter anymore. Even the Lenscap won´t fit anymore...

So i have no idea what to do. Asking for help. Thanks a lot. I need to get this fixed asap because I´m leaving on Wednesday for a two month trip...

Thanks for your help!

rawmeyn said...

I´m new to FD lenses. I guess I have newFD lenses. But I put up a picture here, maybe that helps?

Picture Link:

rawmeyn said...

alright, i fixed the problem. The lens was just too loose with the adapter connected... so u don´t have to approve all my comments haha ;)

obakesan said...


sorry, I approved before reading carefully ... glad it all went well!

have a good trip!

amsanchez86 said...

Where did you purchase the adapter?

obakesan said...


as he's an eBay seller I bought it on eBay :-) I'm unaware of any other way to buy from him. Most of the best adaptors (including the Ciecio7 one) are on eBay ... the ones in shops will cost about 2 or 3 times more and .. well ... aren't any different.

Bruno Afonso said...

You can buy RJ adapters through rainbow imaging that is NYC. Either through amazon or ebay

wsanders said...

Question - Is the "RJ" adapter the same as the "jinfinance" adapter?

obakesan said...

jinfinance is an eBay seller
RJ Camera adaptor is sold by them (among others now).

I think that jinfinance has something to do with the manufacture, but I'm not entirely certain.

Perhaps he used eBay to start interest in his line of stuff?

so ... probably

Anonymous said...

Why would anyone spend minutes fiddling with a device and not explain what they were doing?

You write that one turns the adaptor ring to allow the lens aperture to go to its setting. But, what happens with the adaptor ring after you turn it?

Does it spring back?

Do you need to manually turn in back?

And, you never explain what must be done open the aperture for focusing!

And, what are you doing sticking a pin into the adaptor?

Why are there two pins you fiddle with?

obakesan said...

Dear Anon

thanks for your comment. I'll try to answer a few of your questions.

>Does it spring back?

no it does not, you turn it to bring it back.

>And, you never explain what must be done open the aperture for focusing!

well, that's because I can't write a full book on photography in a single blog post. The answer is that you can focus with more precision on a point with the aperture open then when you stop down you bring in the depth of field deeper in front of and behind the subject.

>Why are there two pins you fiddle with?

I recommend you get an FD lens and play with it. One is to open and close the aperture the other is to set the aperture size and also tell the camera mechanically where it has been set to.

This is something in the history of TTL metering on cameras. I might do a blog post on it