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I just modified my Iscorama 36 for close focus


richg101
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*Edit* tested at f1.8, it doesnt seem to degrade the sharpness. have a look at the image link I post later on this page.

the mod involves removing the ring which has 'iscorama 36 1.5 isco gottingen' printed on it, unscrewing the 4 retaining screws. Then filing away the 'stopper' on the inside face of the ribbed part of the plastic body which you grip onto while focusing. this allows the focus ring to turn approximately double the 'throw' it does as standard. as standard the focus throw is exactly 1/2 a full turn. with the stopper removed you can spin the ring a whole turn before you start to get dangerously close to running out of thread on the main focus element barrel.

At the moment, I have yet to add a replacement 'stopper' at a different location on the inside face of the focus ring. this means if I go further than a full turn from infinity, I can completely unscrew the front element. I have noted the maximum safe amount so this isnt a problem for now, but I will add a new stopper when i decide where I want the minimum focus to be.

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This is great news, Rich! No need for the expensive Van Diemen mod now...

 

I don't suppose that you took a photo while you were working on it?

 

no.  due to it being such a worry - (I didnt know what was going to happen when the 4 screws were removed) I wanted to be in full control of the parts and not worry about documenting it.  

 

Based on your previous stuff you have done I think you will be fine man.  be careful removing the 'iscorama 36 1.5x isco gottingen' ring.  then carefully remove the 4x screws - they are very soft metal so make sure you have a precision screw driver the right size.  

 

the 4x screws just hold the plastic housing in place - they dont hold anything else in place from what it seemed.  Once you are at this stage you will see what needs to be done.  just use a dremel multi or similar mini grinder to shave away the stopper on the inside of the plastic focus ring.  There are 2 stoppers - one for infinity, and one for minimum focus.  it'll be apparent which one does what once you are inside:)

 

then wash the plastic focus ring under a tap and dry properly to remove any sanding dust before re- assembly.

 

when re assembling, set the focus ring and the front element barrel to infinity (you can use the dabs of glue (which was put on in the factory to stop the screws untightening) as a guide so infinity focus matches the infinity point on the focus scale.  You might need to tweek it back to exact while on the camera, but using the glue marks as a guide was good enough for me.

 

just remember to not completely unscrew.  dont go past the infinity mark on the scale - the focus thread is VERY TIGHT!, and might get damaged if you completely unscrew it and then cross thread it when screwing it back on.  I will probably just work out my prefered closest focus based on sharpness/close focus ability and put a short m3 bolt through the ribbed plastic focus ring part so the bolt end stops it turning too far.      

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Comparison Image:-

https://www.wetransfer.com/dl/0Ljy7XxE/07fbd6c56caaee74716729a4ce56db222d9c237dba89b8f0afa4ae5603400f28f5d3711b6e72ae3

Each image was taken by setting the minimum focus on the Iscorama then moving back and fourth until the image was in focus. I then tweeked the focus ring slightly to make sure it was bang on. There has been no cropping to any of the images. this is exactly what the sensor saw. The closer shots are because the camera was physically closer to the cat, there has been no cropping or zooming. fyi, Point of focus was on the cats cheek where his whiskers grow.


As you see, the modification now allows me to get as close to the subject as i use to be able to using the tokina. adding the tokina to the isco 36 now it has been modified allows me to go really close.

each image was taken by getting as close as i could to the cat before i ran out of focus ability. As you will see, the modification doesnt seem to affect sharpness at all. and allows the isco to go as close as with a tokina, without the tokina. the tokina added to the modification allows really close focus!:)

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Comparison Image:-

 

https://www.wetransfer.com/dl/0Ljy7XxE/07fbd6c56caaee74716729a4ce56db222d9c237dba89b8f0afa4ae5603400f28f5d3711b6e72ae3

 

 

As you see, the modification now allows me to get as close to the subject as i use to be able to using the tokina.  adding the tokina to the isco 36 now it has been modified allows me to go really close.

 

each image was taken by getting as close as i could to the cat before i ran out of focus ability.  As you will see, the modification doesnt seem to affect sharpness at all.  and allows the isco to go as close as with a tokina, without the tokina.  the tokina added to the modification allows really close focus! :)

Rich, this is huge. You are an innovator and a pioneer in the world of anamorphic shooting. With your discovery, my Iscorama becomes twice as usable. My hat is off to you!

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if you struggle to grip the initial ring that needs to be unscrewed, wash your hands with soapy water to remove grease and put a little double sided tape on the end of each finger so they grip to the face of the ring.  there is nothing to grip on to so you need as much friction between your fingers and the face of the ring as possible.  you might need to wash your hands repeatedly so there is as little grease as possible otherwise its very hard to get the ring spinning.

 

also, maybe mask over the front element with a bit of low tack masking tape too.  just 'de sticky' the masking tape by sticking it to the inside of your arm, and pull it off and repeat till the sticky is less sticky:)  

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if you struggle to grip the initial ring that needs to be unscrewed, wash your hands with soapy water to remove grease and put a little double sided tape on the end of each finger so they grip to the face of the ring.  there is nothing to grip on to so you need as much friction between your fingers and the face of the ring as possible.  you might need to wash your hands repeatedly so there is as little grease as possible otherwise its very hard to get the ring spinning.

 

also, maybe mask over the front element with a bit of low tack masking tape too.  just 'de sticky' the masking tape by sticking it to the inside of your arm, and pull it off and repeat till the sticky is less sticky:)  

 

Good hint. I'll try that.

 

Nice mode dude. I did the same to my Isco Centavision and it worked well. The Iscorama 36 I have not tried yet so this info is particularly useful to me.

 

What's the min. focus on your Centavision post-mod?

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Just tested again.  seems maximum  'optimal' additional focus throw adds slightly over 1/4 of a turn extra to the existing 1/2 turn as you get on a standard iscorama 36.  so total throw is 3/4 of a full turn.  it will go a full turn, but you get a bit of wobble due to what feels like a lack of thread to keep the two parts linear.  I am going to set my new stopper to 3/4 of a turn away from infinity.  This gives me about 1ft closer focus than a standard iscorama 36 with the +0.4 diopter, and probably about 2-3ft closer than the standard iscorama when not using a diopter.  

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Success!

 

I have completed Rich's "surgery". I am now able to focus at 3'2" without a diopter (any further and lens begins to wobble), wide open at f/1.8 and seemingly without a loss of sharpness:

 

gallery_18451_14_1195074.jpg

GH2 with Nikkor 50m f/1.8 AI-S @ f/1.8 and newly-modded Iscorama -- this is how close I am able to get.

 

I did superglue in in my own jury-rigged limiter, but the throw of lens is so far now that it isn't making contact. I'll probably just put a red tape mark on the lens to indicate the closest that I dare to focus (though it's very obvious when you've gone too far).

 

Today is a good day. Thanks again, Rich, for having the guts to be the first to open up a $3000 lens and poke around.

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I have been trying for an hour to remove the front "Isco Gottingen" ring. It's on there pretty good. I have washed my hands many times. I've tried latex gloves and rubber bands, but nothing is budging.

 

EDIT: Rubber-dipped gardening gloves did the trick on my first try.

hahahaha.  nice one.  I wouldnt have even thought of rubber dipped gloves.  based on my experience too, this it definitely the best option.  perfect 'shore rating' of rubber to grip onto that slippery ring.

 

 

 

for those worried, the process is quite nice because once you get the ring and the screws off, you can see straight away if the job is above your capabilities.  if so, just replace the screws and screw the ring back on.  setting the lens to infinity at the start makes everything more logical when you get inside and then want to put the thing back together.

 

using a dremel multi tool grinder wheel to shave off the stopper on the inside face of the plastic outer housing is easy as long as you take it slow with the dremel on minimum speed to ensure you dont grind right through the plastic.  you need good light and a nice work area. you just need to make sure you choose the right stopper to grind off (there are two - one for infinity, and one for minimum focus).  if you dont have a dremel tool, you could even shave the stopper off slowly with a scalpel in thin layers - the plastic is easy to cut away at. 

 

once you are modified, the original minimum focus distance was where the red line lines up with the '2' on the metre scale.  

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Success!

I have completed Rich's "surgery". I am now able to focus at 3'2" without a diopter (any further and lens begins to wobble), wide open at f/1.8 and seemingly without a loss of sharpness:

gallery_18451_14_1195074.jpg

GH2 with Nikkor 50m f/1.8 AI-S @ f/1.8 and newly-modded Iscorama -- this is how close I am able to get.


I did superglue in in my own jury-rigged limiter, but the throw of lens is so far now that it isn't making contact. I'll probably just put a red tape mark on the lens to indicate the closest that I dare to focus (though it's very obvious when you've gone too far).



Today is a good day. Thanks again, Rich, for having the guts to be the first to open up a $3000 lens and poke around.



maybe work out the minimum focus point you can get where your new stopper/limiter still works and set it for there? at 3.2' that front element is about 5mm further out so wont be near the contact tab it is meant to hit. I bet it is not massively far away though.

I think we need to figure out some sort of external stopper. or, modify the other section of plastic housing where the stopper contact tab is attached. so the new stopper/limiter can be brought further down slightly so it still makes contact with the tab. if we just put a stopper in a position where it still makes contact with the tab at 3.2' minimum focus the stopper wont allow the focus ring to wind all the way back and reach infinity, so the points where the stopper might fowl would need to be cut away. though, this will render the lens always having a sma gap so you can see the metal front element housing even when taken back to factory if that was ever required. I think I will do this because I dont see myself ever selling the iscorama now. and i feel the modification adds value to 90% of users. collectors might not be that keen, but mine was never a collectors piece before I got it, and gets used regularly.
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