Frequently asked questions


May I link to your site?

Of course.

Can we exchange links?

I don't exchange links just to attract more visitors. If you have relevant pages I may link them, regardless of whether you link to my site.

Can we exchange banners?

I have no banner.

Can I advertise on your site?


Can I use this photograph for my desktop?


Can I use this photograph for commercial purposes?

Here I would need to charge a fee. Contact me with the details.

May I use this illustration in a publication?

Yes, if you properly reference it. If you intend to use a lot of material from this site for a conference or journal paper, it is good practice to ask for permission.

I want to use your illustrations in a forum discussion, but they don't show.

Hotlinking is not allowed.

When will your book appear?

There are no concrete plans for a book.

Will you give a lecture at our photo club?

Unfortunately I live on the other side of the Atlantic.

I see some strange phenomenon in my picture. Do you know what causes it?

Perhaps. Show me the photo and inform me about the picture taking conditions.

Can you help me with the design of a lens for this or that application?

That is unlikely. My attempts to understand the causes of image degradation in photography do not make a qualified lens designer.

Will this hood, or that filter, vignette on this particular lens?

It is possible to answer that question by calculation, if all relevant parameters are known. Since I don't have the parameters for this hood, that filter, or this particular lens, I don't know the answer. The best way to find out is to take pictures with the combination.

Which software do you use to build and maintain your site?

It is called UltraEdit.

Why did you not answer my e-mail?

There was no question in it.

No worries. Serious, nonanonymous e-mail is usually answered.

Why did you not answer my e-mail?

The spam filter got it.

Why did you not answer my e-mail?

I was away for six weeks.