Custom aperture blade attachment?

[Overread]

Just wondering, I know there are a few adaptors (eg canon to micro 4/3rds) which allow the mounting of lenses to bodies whilst also providing a manual aperture blade setup on the adaptor itself so that one can have aperture control when a mechanical/electrical communication between lens and camera is not possible. However I was wondering if there is such a device designed purely for adding a finer grading/circular blade setup into an existing Canon to Canon setup *ie a canon lens onto a canon body*.


The reason I ask is that the MPE has a poor set of aperture blades, which give a fairly angular edge to the highlights (which can be a problem with stacking sometimes). So an adaptor like this - even if custom built from hacking up a regular adaptor for other mounts - would give a chance for a more rounded aperture blade setup - whilst the added adaptor would not be affecting the use of the lens itself (since it has no AF and no infinity focus).

 

[Edsport]

You can have aperture control with a lens that don't have manual aperture control. The way to do it is to put the lens on the camera in the normal fashion, set the aperture you want and then hold in the DOF button, while holding it in remove the lens from the camera. The lens now has the aperture set. Not sure if this info is useful to you or not. Someone said this may not be safe but i've done it many times without a problem but Use at own risk...

 

[Overread]

Ahh yes that is true, but you've missed the point

I've already got aperture control over the lens, but the blades within the lens itself are very angular and cast a less than circular highlight - thus I want to be able to add a custom set of aperture blades before the lens so that I can create a more well rounded highlight effect. As said its purely for macro work on a macro lens so pure it can't even work outside of macro magnifications; so adding distance from the adaptor between lens and camera body (like extension tube) won't be a hindrance.

 

[Derrel]

Hmmmm....kind of wondering if one might be able to use simple round discs, like those used in the Lensbaby 2.0 and other later models; these are little more than flat,metal washers, held in place by a magnet. Is the front element of the MP-E deeply-recessed and small? As it is on a Lensbaby, or say a 55mm f/3.5 Micro-Nikkor? "Maybe" a fellow could use simple, perfectly round-apertured discs???? Might be worth a try.

 

[Overread]

I've had that idea suggested, though I thought that the addition of a aperture disk would be best behind the lens rather than in front (ie disk slipped into an extension tube) or would it make no noticeable difference ; only what with flash units and the like I'd be running the risk that having the material out front over the lens might cause some optical problems whereas behind inside the lens it might be a lesser problem

The MPE has got a small recession (nothing like as deep as on my 70mm or 35mm) and with a tiny front element and I've already got two tabs of velcro inside the main housing area (to attach diffusion adaptors to).

 

[sleist]

I have seen where people use star or heat shaped 'irises" in front of the lens front element to create star and heart shaped highlights in the photos. Some decent examples used a piece of cardboard. A sharp circular cutout as Derrel suggests may be more effective than you might think. Google star or heart bokeh. No reason this wouldn't do what you are looking for with just a perfectly circular cut out. You may need to experiment with size to get the right mix of effect without degrading the image too much.