64 votes
Accepted

Why are some big telephoto lenses so expensive compared to telescopes?

Rarity. There were only approximately 20 of these now out of production lenses ever made. When they were in production they sold for about $90,000 (US). Due to the time needed to grow the large ...
  • 169k
15 votes
Accepted

What is the relationship between focal length and minimum focus distance?

It depends entirely on how the lens was designed, there is no general formula or way of determining the minimum focus distance. Lenses of the same focal length can have completely different minimum ...
  • 117k
10 votes

Why there are so few lenses with small minimum focus distance?

Because most interchangeable lens cameras typically use larger-format sensors than 1/2.3"-format. The close-focusing capability of most small-sensored compacts comes from the fact that small sensors ...
  • 49.4k
9 votes

Why are some big telephoto lenses so expensive compared to telescopes?

Michael Clark missed one important point in his otherwise correct answer: Physical vs. Optical length Think about what the 1200mm really mean. This is the focal length. This normally means that the ...
  • 842
8 votes
Accepted

Why there are so few lenses with small minimum focus distance?

I've found that for interchangeable lens camera lenses (at least for Olympus micro for thirds lenses) the minimal focus distance in the specs is measured from the sensor, while for compact cameras ...
8 votes

Why there are so few lenses with small minimum focus distance?

The focal length of a lens is a calculation made when the lens is imaging an object at infinity. This is a distance as far “as the eye can see” symbol ∞. As we focus on objects nearer than infinity, ...
  • 36.5k
4 votes

New camera won't focus while zoomed in, old one focuses perfectly. Why?

I would suggest trying your SX740 again, but use a far more conservative zoom setting. It should reduce your minimum focus distance to a workable level. The long telephoto setting is for making ...
  • 2,275
3 votes

What is the relationship between focal length and minimum focus distance?

There is no direct relation between focal length and minimum focal distance. Usually a long focal length means a long minimum focal distance, but that is just because a lens built that way also has ...
  • 20.8k
3 votes
Accepted

What is this style of photography called?

The most general term I can find that has reliable returns from google image search is "high contrast monochrome photography" Some of the key stylistic points appear to be a strong use of broad areas ...
  • 2,275
3 votes
Accepted

How is a lens's listed minimum focus distance affected by zoom?

It ultimately depends on the design of the specific lens model (which you have not provided). Most, but far from all, telephoto zoom lenses have roughly the same MFD over their entire focal length ...
  • 169k
2 votes

New camera won't focus while zoomed in, old one focuses perfectly. Why?

I agree with TheLuckless - point and shoot cameras like yours have Macro settings and can actually get quite close to things. As you zoom in, the minimum focus distance increases. You'll have to ...
  • 20.3k
2 votes

What is this style of photography called?

My dad would take photos of equipment (Military electronics, mechanics, tech-guts for the lack of a better term) They didn't always have a black background, but then the background was usually part of ...
  • 83
2 votes

What is this style of photography called?

As Tetsujin commented, I'm pretty sure it would be called "Noir." There's also a filter on the camera app on iPhones with that name. I attached a screenshot of that below.
  • 121
2 votes

Options to increase magnification when the minimum working distance is fixed

1) Would extension tubes be of any benefit here, since the camera/lens cannot be moved closer to the object? Stated in a general way, if the distance between the lens and object remains fixed and an ...
  • 31k
1 vote

How to calculate extension tube length when the focal length is unknown

There are several ways to do this calculation, I like this one: A 16mm has a power of 1/16 x 1000 = 62.5d (diopter) Focused to 1 meter the lens racks forward? Convert 1000mm to diopter 1/1000 x 1000 =...
  • 36.5k
1 vote

Options to increase magnification when the minimum working distance is fixed

If you are unable to obtain a suitable macro lens, you may be able to achieve what you desire by using both teleconverter and extension tube (or diopter filter). Extension tube alone would allow you ...
  • 26.4k
1 vote

What's the best choice of lens from an optics surplus shop to get a Stanhope Lens-like magnifying function?

Because your plan is to mount a supplemental close-up lens, in direct contact with the surface of your camera phone, you believe this added lens must have a very short back focus. This is incorrect ...
  • 36.5k
1 vote

How do focal length, minimum focus distance, and magnification interact on a lens?

I suppose it might be theoretically possible for a zoom lens design to have a shorter MFD at a shorter focal length, but I've never came across such a lens. Most zoom lenses have an MFD that is ...
  • 169k
1 vote

Why there are so few lenses with small minimum focus distance?

A further consideration is that most macro work is (partially) front lit. This gets harder to do the closer you get to the front element. Even ring lights have a minimum useful distance imposed by ...
  • 3,612
1 vote

Why can lenses only focus from so close?

Some reasons off the top of my head: Lenses are full of flaws, designers try very hard to reduce these flaws using different glasses and groupings of elements. This correction varies by focus ...
1 vote

Why can lenses only focus from so close?

A given lens's optical formula can shift groups of elements in the lens around only so much to achieve focus. If you wear corrective glasses or have a magnifying glass, you can simply see how this ...
  • 12.3k

Only top scored, non community-wiki answers of a minimum length are eligible