I'm sure he's right that you'll improve in a single field if you stick to that alone. However you get pretty close to 'mastering' multiple fields without making photography boring by limiting the forms you play with.

It may be that reducing the range of photography shown on your site might increase the amount of work it generates.
If I was after a product photographer, I don't think the quick look I gave your site would have inspired me to pick you, as I'd be after a specialist in the field who knows all the tricks etc. It may be that you're well up on most of the tricks, but memories of photo shoots my Dad had done tells me how meticulous the field is...
The general high quality of the images could well have got me to shortlist you as a wedding photographer if I needed one (Not a role I fancy) - fortunately I should have at least 10 years before it gets to that. I suspect having the eye for a shot counts for quite a bit in wedding photography & your creativity is bound to be an advantage there, as it is in portraiture.

Many if the sections in your Gallery I wouldn't expect to generate commissions, instead being more like a better quality version of my Flickr collection - a (hopefully) interesting collection that have been fun to create. However these are the sections of the gallery that interest me most, acting as inspiration to try something similar, and are I suspect more likely to attract students for your courses & generate business in that way.

If your happy with the business your site generates, there's no point in changing it! Increasing your income at the expense of making photography just work (ie no longer enjoyable) is I think a backwards step.

For me though photography is definitely a hobby & I don't seriously expect to ever get a month where it earns me more than it costs me in that month.

You have a faulty detector then
Having the right to use a brand with a product doesn't mean you have to, if another better seen brand is appropriate you'd generally use that.

IIRC Hoya were interested in Pentax's medical imagery business not camera side of Pentax when they brought them. The press releases I've seen indicated it was always their intention to sell off the cameras, which they have now done to Rioch who were after the cameras side of the business. It's quite common to buy companies for a part of their business portfolio & to then sell the remainder - this may be nothing to do with the profitability of either section & usually is more to do with how that section meshes with their own portfolio.

Lens arrived safely. As usual I managed to be out for the first delivery, or I'd have been able to play with it over the weekend.
Thanks for the prompt service Danny.

Quite right Chris.

Earthshine is what enables a new moon to be seen, lighting (very slightly) the portion of the moon away from the sun. It is similar to seeing at night from moonlight, and will be most visible when the moon is darkest.
(The red glow seen on the moon during a lunar eclipse is different being due to refracted sunlight)

There may be instruments that would be capable of measuring the earthshine on the bright side of the moon but they'd have to be in space - all the surface of the moon visible from down here will be lit be earthshine & it can only be measured againt a reference portion that not got it.

I suspect the bright rim is more likely to be an artifact from sharpening.

Payment made.

My K100d is my backup body for the moment. I'd rather like better high iso capability but can't justify the K5 or Kr this year. I NEED a replacement car...

I've tried a 600mm mirror lens, & have got good results hand held with the K100d in good light. Not yet tried it with the K7, where the extra pixels will be a bit less forgiving (and allow more of a crop from my F300). Unfortunately the Bigma/Bigmos etc. are out of my price range.

There is also the option of connecting your camera to a spotting scope. My Tasco scope isn't really up to the job - It works out as a 1000-4000mm zoom with no aperture control (f16-f64 depending on zoom) but budget optics show (it was only £60) I should imaging a Pentax scope would be MUCH better!

PM sent RE lens - I've already got a K7

I think it was probably my influence. I brought my K7 at the beginning of last month, so there was BOUND to be a glut of them at better prices shortly afterwards!

I don't have any experience with the 28-200, but the 50-200 is great value for money. Mine has always performed well.
If you are after a bit more reach the F100-300 might suit your budget too (generally good examples go for ~£80) It is a bit heavy, & can be slow to focus but otherwise works OK. (I gather the FA versions are lighter but more expensive...)

More modern cameras have enogh pixels in hand to crop images that the longer lens is less useful with my K7, but with the K100d mine got used quite a bit. (I think it might be time to turn it out of my everyday bag & save my back a bit!)

That depends on the Bellows. I've got three different sets & I don't think any have a built in focusing rail. (The BPM one might have but that came with a Nikon mount so I've not used it)
I have got focusing rails too, one set of which only cost £20, making the budget £12 bellows highly usable.

Bellows are one of the most flexible macro options, but they're not fast to use/focus so they're not to every-one's taste.

The old Boots close up lens I've had for 20 years is about as much use as a child's magnifying glass. But better quality achromatic ones can be well worth using.