Focal Reducers - Squeeze all your FOV and Light on your GH1 Sensor

Do you retain DOF with focal reducers?
yes. its the same image circle. it will look like the native capturing lens.

Then where were these during the EPIC Edwierdo thread?
 
TimurCivan said:
perhaps im misunderstanding... do you have a focal reducer on your medium format lenses? because a 80mm would look like a 105 or 110 on a 35mm Film plane.
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That´s what I thought and everyone told me in the first place - but it´s wrong.
With a 50mm medium format Zeiss prime I get the same FOV and DOF as with a 50mm Nikon prime made for 35mm photo cameras on my LEX.

Don´t ask me how it works but it´s a fact. Look at the pictures:
First one is 4.0 50mm Zeiss medium format
Second one is 1.4 50mm Nikon (35mm photo prime)

And no, I don´t have a reducer. I just mentioned it because there was always some missunderstanding when it comes to medium format lenses.

But I wish I would have a reducer or even better an anamorphic reducer.
 

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A 50 is a 50 is a 50 is a 50 - regardless the size of the chip.
The difference between a 50mm SLR Lens and a 50mm medium format lens is the size of the image circle.
If you add a focal reducer or doubler it's no longer a 50.

There's a lot of 'crop factor' confusion out there.
 
Sorry to revive this but it was tointeresting to keep it out.

What's up yet with Focal Reducer?
 
I've been wondering, does a focal reducer change the back focus distance (focal flange distance) of the photography/telescopic lens?

If it doesn't it seems impossible to fit any focal reducer between GH1 and lens, even if an adapter was made to move the FR within the camera body towards the sensor
(about 20mm of space from Micro 4/3 mount to sensor).

All the focal Reducers I've found have a focal length greater than the focal flange distance of a Nikon lens (46.5mm).

For example, according to http://www.wilmslowastro.com/software/formulae.htm#FR

the focal length of the following Focal Reducers are:
- Atik 0.5x = 80mm
- Celestron 0.63x = 285mm
- Meade 0.33x = 85mm

The Meade/Celestron focal reducers have the following focal lengths.
[note: Since around 2006 Meade 0.63 focal reducers have a focal length of around half what they should be making them unsuitable for use with SLR cameras or filter wheels]:
FR 0.33x focal length = 85mm
FR 0.63x focal length = 285mm
​
William Optics 0.8x FR focal length = 260mm
ATIK 0.5x FR focal length = 80mm
* Note that the in-focus figure assumes that the FR-CCD spacing is added to your physical imaging train length (as when using the Meade/Celestron FR's with spacing tubes). If you are using a FR like the ATIK that is fitted internally, then you have to add the FR-CCD spacing to this figure (to make it smaller). If you are using a FR like the Meade/Celestron then you will have to subtract the depth of the FR itself to this figure (to make it a larger negative number).
Click to expand...

Anyway, I think this thread may be a lost cause now.
 
focal reducer

focal reducer

read here :

http://www.bautforum.com/astronomic...cessories/55902-focal-reducer-slr-camera.html

"I've never seen one and there may be a reason. Putting in a FR requires shortening the distance between telescope object and the FR versus where the sensor (film) would normally be without it. For example, I have an Orion ED80 telescope and a 0.5 focal reducer. The FR should be (and normally is) a fixed distance from the sensor (film) as this distance determines the actuall reduction amount - more distance = greater reduction. Without the FR, my camera can't focus without adding about a 2" extension tube to the optics train. With the FR (at a distance that yields 0.5x) in its proper place at the end of the camera's 'snout' the focus is just fine without any extension tube. By using a longer 'snout' to achieve more like 0.4x or 0.35x ), the camera cannot go into the telescope's tube far enough to focus.

Consequently, I would expect that to insert a FR in a camera/lens system, one must move the lens away from the sensor (film) in order to insert the FR while the optics demands that the sensor (film) be located closer to the lens if there is a FR added - which in the general case is likely to be an impossibility.

On the opposite end of things, barlow lenses used to be available for slr cameras for 2x and 3x increase in effective FL. However, those require separating lens from sensor (film) which was no problem."
 
I see no reason why a focal reducer can't work on the GH1 and the first person who sticks a Micro 4/3rds mount on the end of one is going to be a millionaire :)

Yet a quick look around and they're all for telescopes! Crazy...

The diagram of the old Nikon DSLR with small CCD sensor showed the imaginary film plate behind the lens. The lens works as normal and the focal reducer simply delivers the image to the sensor at half the size and double the brightness.

I can't wait for somebody to actually make one... it can't be that hard? The optics already exist.

My only concern is over image quality. Sure the image will be brighter and you could probably get away with lower ISOs than you normally could, but the lens won't be more sensitive to light. It'll still be an F1.4 for example. It's just that the sensor will be more sensitive to the image. But I bet that some subtleties from the image will be washed out and the focal reducer would have to have some damn good glass in it to keep hold of all the image's resolution at 0.5x.
 
So any updates on this? i'm looking to shoot a feature soon and it would be awesome to have a focal reducer instead of investing in 7.5mm lenses.
 
yeah, I'm real late to the party- but this sounds great--very Edwierdo thread-ish!! I love it- another holy grail to chase.

Anything...

Anyone??...

Z
 
Hey Guys'

Me interesting this theme too, I'm bought 0.5x Focal reducer. Fastest test show very nice result. I'll do new adapter for this reducer and show result.

Test result will be soon. ;-)
 
NURBS,

Where did you buy the 0.5x adapter? How did you attach it to the GH1?
Yes, please show the results of your test soon!
 
First fastest test from a hand, reducer photos have lot of flares and optical distortions. (soon will be with new adapter). :Drogar-BigGrin(DBG)

Nikkor 50mm f/8
 

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NURBS did you ever get any further with the Focal Redeucer Adapter? Which Focal Reducer did you use? Cheers
 
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I've succeeded in adapting a 0.6x focal reducer to my E-P1. This forum thread helped me a lot, which is why I'm eager to share the results soon and keep this topic alive.

Originally, I hoped to use it on some of my longer C-mount lenses, like my Fujinon 50/1.4. However, due to the micro 4/3 flange focal distance, it's impossible. Forget about Olympus and Panasonic lenses too. Nikon lenses work though. I've tested with a Rokinon 8/3.5 fisheye and Nikkor 105/2.5. My guess is that T-Mount lenses would work as well, with proper adapters and/or adjustments.

Because the focal reducer is 0.6x, I get sensor coverage that's maybe slightly bigger than APS-C but definitely not full frame. Quality-wise, the results are similar to what NURBS posted. I get a decently sharp picture, but lower contrast. Lens speed is doubled.

As for DOF, I don't know yet. I'm still trying to fashion a proper mount for it. My workmanship is kind of shoddy (metal file and super glue for everything), and I'm only using some spare parts I have at hand.
 
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