mark_hubbard

<p>Jacques,<br> Thank you for your response and especially for posting the link to your beautiful night photo of Hong Kong, which is sharp and clear across the frame. I would enjoy seeing other images you've made with this lens, especially any in bright sunlight. You mention that the Mamiya repair center told you the lens has a floating element which, if I understand correctly, might make it the "ULD" version. Is that the case? Currently the 50mm ULD fetches two to three times the price of the non-ULD versions on the used market. I'm wondering if the premium for the ULD floating element is worth it. <br> The use of UV filters has always been controversial among photographers. They do block UV light, as does window glass. Some people use them on all their lenses; I don't own any. If I'm going to photograph someone at the beach along our foggy and windy far-northern California coast and want to protect my lenses from salt spray, I prefer to use a warming filter. When it comes to whether or not to use UV filters at all, I politely refuse to argue the point.<br> This discussion has been useful to me, because I've had my eye on a couple of lenses for my RZ that are steeply discounted due to internal fungus or mild hazing, and I want to learn all I can about how these defects impact image quality, if at all. Any additional examples you can offer taken with your lens would be greatly appreciated.<br> With kind regards,<br> Mark H.</p>

<p>QB:<br> You wrote, "If the fungus does indeed not have a noticeable impact on image quality, you could try to stop further growth of the fungus using a UV light to kill it." Just to clarify, this may work on the outside of the front and back elements, but it won't work on internal fungus, as the glass will effectively block almost all of the UV radiation. I own long-wave and short-wave UV lights for examining fluorescent minerals, including an $800 SW UV light. Even this big light doesn't penetrate glass, but after reading your post, I may try it on fungus to see if it helps. The inexpensive "black lights" you can buy at novelty stores are weak long-wave UV only, and are useful mainly for entertainment purposes, not sterilizing. I encourage anyone who is interested in learning more about the science and enjoyment of using UV lights to consider joining the Fluorescent Mineral Society.<br> With kind regards,<br> Mark H.</p>