Are any front-mounted 2x attachment converters very good?

E. von Hoegh

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jeffreyg said:
I am quite sure Hasselblad doesn't although they have Proxars for close-up. I'm not familiar with lens construction but I suppose one could be designed. Since the setup I have gives great results I'll stick with it.
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When behind-the-lens converters are designed to work with specific lenses, the performance can be very good. Before-the-lens attachments can work very well too, look at the Rolleikins for closeup.
 

AgX

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Is a closeup-lens (Rolleinar) a converter? I would say no, it just adjust focusing. (A closeup lens should at least be made of two elements, a Achromat.) A converter or a converting attachment does give the new combination a different angle of view.

I'm not sure about the cause for barrel distortion with before-the-lens converters. I do not think it is related to the FL of the prime lens.
 

StoneNYC

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I didn't see the part on post #4 because I was skimming, but it says in the same post "made by canon and Nikon" and canon only makes a back attaching extender as far as I've ever seen, so thought he was speaking about those.


Sent w/ iPhone using Tapatalk
 

David A. Goldfarb

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Canon and Nikon make front mounted converters for video cameras and digital P&S cameras with fixed zoom lenses.


The diameter of the rear element is one factor, but for extenders, the general optical design is also a factor. I have Nikon 2x and 3x front mount converters that require the lens to be zoomed toward the tele side--even with the camera they were intended for--to work without vignetting.
 

LunoLuno

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And if I remember correctly, Canon made front mounted converters for their Sure Shoto (AKA Autoboy) series cameras back in the 80's.
 

Paul Howell

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Most that I have seen over the years were made for 60-70 vintage Rangfinders, Kowa, Petri, Yashica, I recall seeing converters sold in the PXs at the time. I dont recall any that were very good, at one time I considered getting a Yashica and a tele coverter for soft focus portraits, they were for the most part poorly reviewed in the mazs of the time. The lens made for leaf shutter SLRs and rangfinders, like the 35mm and 80mm for the Retina, were sort of a converter, the front element was replaced with a new element and were much better than the screw on type.
 

AgX

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One wide-angle attachment I got has a front group from amber glass. Puzzling.
 

Xmas

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the camera manufacturers own brand were reasonable for long lenses and saved both $ & space in gbag as were some of the 3rd party there were large cost differentials when new. Packing a 135 prime and a 270 prime difficult. The alternate zooms have dominated *SLR sales.
 

lxdude

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LunoLuno said:
And if I remember correctly, Canon made front mounted converters for their Sure Shoto (AKA Autoboy) series cameras back in the 80's.
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True. I was given a Sure Shot with both the wide and tele converter attachments. One of these days I'm going to try them out.
 

thuggins

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benjiboy said:
No, not to me they aren't Darin, because with any 2X converter whatever the optical quality of the converter you lose 2 stops in aperture effectively reducing the film speed to a quarter of it's normal speed .
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Wow, this post has gone all over the place. But to get back to the poster's original question, the front mounted converters do not lose two stops. Olympus made T-CONs of 1.5X, 1.7X and 1.9X for their revolutionary IS series cameras. These mount to the front filter threads of the camera, the optical quality is excellent and they lose little to no speed on the lens. This is because the front mounted convertors have a larger objective lens so they are able to gather more light.

The focal ratio of a lens = focal length/front aperture. With the rear mounted teleconvertors you were still locked in to the diameter of the original front lens element; hence the loss of aperture. I have used the T-CONs on various lenses from 50mm up to 200mm with very good results. The Zuiko 200mmf5 with 1.9x T-CON may not be quite as sharp as the 400mmf6.3, but the combo is a heck of a lot smaller, lighter and cheaper. In fact, the lens and the T-CON will each easily fit in a pocket.

The A-200 is 1.5X and has a 49mm thread. The B-300 is 1.7X and has a 55mm thread. The C-210 is 1.9X and has a 52mm thread.
 

David A. Goldfarb

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Thread title updated, better late than never, in the hope of keeping things on track.
 
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