E-M1 Infrared Conversion: Good or Bad Idea?

[drmarkf]

As far as I know the glass element for a m43 camera must be 3mm which is the thickness of the AA IR cut filter. If the convention use different filter may result to focusing problems.

Are you sure?

That would be true for a DSLR, but mirrorless systems focus on the sensor, so surely it's either in focus or not and anything in front or not won't affect that as long as the lens is still capable of focusing on infinity.

 

[Skeeterbytes]

As far as I know the glass element for a m43 camera must be 3mm which is the thickness of the AA IR cut filter. If the convention use different filter may result to focusing problems.

Are you sure?

That would be true for a DSLR, but mirrorless systems focus on the sensor, so surely it's either in focus or not and anything in front or not won't affect that as long as the lens is still capable of focusing on infinity.

This sounds plausible, similar to why there's no need to lock focus then adjust for IR, as in the Good Old Days. I still own several lenses engraved with IR shift marks.

Cheers,

Rick

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[kbouk]

I made a mistake , the m43 AA filter is around 4mm , see here : https://www.lensrentals.com/blog/2014/06/sensor-stack-thickness-when-does-it-matter/,

I have mention focusing problems especially at the infinity with some lenses. The sharpness isn’t really effected by filter thickness but from the quality of the filter.

 

[Brian Chichester]

My 590nm filter is a Jessops Red R2. I'm guessing it's not a completely accurate 590nm cutoff but it does the job, bearing in mind a good deal of post processing is going to be done.




IR 590nm cutoff, full spectrum IR converted camera.

 

[drmarkf]

I've had trouble finding the more unusual IR filters, especially those around 590: it appears that Jessops don't sell any at all currently, at least online.

Anyone in the UK or EU got any good sources? I'd be especially interested in 58mm or 46mm screw-ins, but would be happy to try anything with a step-down ring.

 

[Brian Chichester]

The Jessop red R2 filter is not a dedicated IR filter. Rather it is a deep red filter from the good old film days, when we used it to darken skies. These filters are available ( in various brands) on the big auction site: prices are likely to be low because there is little demand for them in their original use.

I'm sure if you put it on a spectrometer you would find it was not a pure 590nm cut filter, but as I said, we have a good deal of latitude in post processing to get the effect we want.

 

[drmarkf]

Great, thanks for that.

 

[kbouk]

I think red infrared longpass filters begin around 610nm wavelength ... from 515-590nm they are orange ...anyhow an alternative to Jessops red filter is Hama R8 : https://www.ebay.co.uk/p/Hama-58mm-...Colour-Infrared-Filter-Black-white/1305194841

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Cheers
Costas