Chris Ross
Contributor
To be clear heat does not cause fogging of housings - that is to say it is not the root cause. What heat does is vaporise liquid water inside the housing allowing it to migrate to a cold surface and condense again - the cold surface usually being the lens port. The real cure is keeping the housing dry inside, whenever you open the housing you risk having drops of water sitting on the o-ring and there is little to stop that getting inside the housing, when you close again. Having something to mop that up makes a big difference. A desiccant pack only absorbs water vapour, and not that much of it, if there's liquid in there you'll very soon exhaust the pack.
On diopters - I would suggest the TG series don't need macro diopters. The diopters work by allowing the camera to focus closer and most will bring the focus point up to touching the glass port surface on a TG - which is why they don't work. The TCON setting is just a kludge that moves the focus point out again allowing the lens to focus again - but you have extra glass involved and the chance of aberrations due to the diopter. The only thing a diopter might do is allow you to remain in normal mode (focuses to 100mm ) and not have to switch to microscope mode to get super close - there may be some advantages to this.
On diopters - I would suggest the TG series don't need macro diopters. The diopters work by allowing the camera to focus closer and most will bring the focus point up to touching the glass port surface on a TG - which is why they don't work. The TCON setting is just a kludge that moves the focus point out again allowing the lens to focus again - but you have extra glass involved and the chance of aberrations due to the diopter. The only thing a diopter might do is allow you to remain in normal mode (focuses to 100mm ) and not have to switch to microscope mode to get super close - there may be some advantages to this.
