Wide angle medium format lens coupling?

[Batspiderfish]

With lens coupling, could I reverse a wide angle medium format lens to get the highest magnification possible, while beating the vignetting that occurs with more sensibly-sized wide-angles? I'm using a Canon Vixia HF S200 (58mm thread diameter,) which has a built-in zoom lens that doesn't quite hit the desired magnifications I got with my Panasonic SDR-T50, which gave me very pleasing results when I reversed a Jupiter-8 58mm over the zoom (that camera doesn't have filter threads, so I had to use rubber bands to keep it on .)

I'm somewhat familiar with crop factors, but my brain is telling me that I should expect the same type of image from a reversed (full frame) 35mm lens as a hypothetical medium format 35mm.

If you can't tell already, I'm somewhat oblivious to the actual science of optics.

I am filming small ants, If you were wondering.

 

[Derrel]

A 35mm focal length lens for a 35mm camera mount is pretty affordable. A 35mm lens that can cover a medium format frame is quite uncommon, and probably lives mostly in the hypothetical realm. Focal length is focal length, but medium-format lenses DO have a larger image circle, but honestly, it would seem that the image circle of most 35mm mount lenses would be adequate to cover any smallish video format without vignetting **if** the lens were mounted via adapter directly to the camera. But in your case, you've got the in-built zoom on the camera with the 58mm threads.

FotoDiox might be the single largest USA source for adapters and step-up and step-down rings. I'd check their web site for leads.

Fotodiox Professional Photography Supplies and Equipment

 

[Batspiderfish]

I have noticed that medium format lenses tend to be long, so I'm probably better off finding a fast wide angle from a 35mm camera? I've tried with a 28mm F2.8, which gave me very good magnification when reversed, but expectedly terrible vignetting.

If somebody could recommend any old wide angles with big glass, that would be appreciated. I'm on the lookout as we speak.

 

[Batspiderfish]

How wide do the rear-elements of 16mm cine lenses tend to be? Possibly a good alternative. Medium format was a dumb idea, looking back.

 

[Helen B]

The rear element of 16 mm cine lenses is often quite small. No hard-and-fast rule, however.

The vignetting problem you are having has little to do with lens coverage, and more to do with the size and position of the entrance and exit pupils of the two lenses you are using. Have you tried to zoom right in with the main lens?

A 35 mm lens is a 28.6 diopter lens. Raynox make 25 and 32 diopter close-up lenses that will fit the HF S200, according to this table. These are multi-element lenses, not simple single-element lenses.

There's a flickr group for Raynox lenses, so it might be worth looking into the Raynox option and whether they will provide the quality and magnification you require.

Best,
Helen

 

[Batspiderfish]

Thank you everybody for your input!

I've considered using a dedicated supplementary lens. They seem to provide very pleasing results that I, fortunately, already obtain with other lenses I own. The reversed 2.8/28mm gives me those jaw-dropping super magnifications, but the small size of the rear element pushes me into digital zoom before I can be rid of the vignetting. I'll probably be able to inch by with a slightly faster lens.

I have Jupiter-9 lens, which has HUGE glass for its specifications (it actually makes me suspicious that it's designed for medium format.) I guess I'm on the lookout for another oddity that will work out well for my plans.

 

[Helen B]

Perhaps you are misunderstanding the meaning of 'diopter'. The Raynox 32 diopter lens is the equivalent of putting a reversed 31 mm lens in front of your main lens. No difference in terms of 'super magnification'. However, if you wish to continue to look for an 'oddity' without understanding what your real problem is, feel free.

 

[Batspiderfish]

I guess I was confused about what you were talking about.

I'm a little wary of investing in this general-purpose macro equipment. I've heard mixed accounts for Raynox; the working distance seems to go to a minimum of about 5cm, while reversing old Minolta lenses put me at somewhere around 2.5cm (does the flange distance of a reversed lens give an approximation of working distance when it's coupled?) Am I right to assume that the farther working distance will give me a lesser "magnification"? I guess all I'm really looking for is a 28mm wide angle with a rear element large enough so I can beat the vignetting without going into digital zoom. The purpose of the lens is for when I want to get very high magnification footage of small insects. I'd really consider buying a Raynox if I could try it out first, but for now I feel safer experimenting with what almost works.