autofocus Loc: North Central Connecticut

^^^This :thumbup: I think it's a combination of a few factors. Yield and complexity in the semiconductor industry will always dictate the cost. I'm also sure that market share plays a role. At the present time, you may say there basically is three grades of dSLR's. Consumer, prosumer, and professional, and all are offered at different price points. It's really no different than what Ford does with it's line of pickup trucks. Different needs or requirements will dictate whether a buyer needs a 150, 250, or 350 series. And by doing this, Ford is participating in a much broader market..and this is no different than what the camera manufacturers are doing with their products.

pecohen Loc: Central Maine

Just like they did with film cameras.

Hmm, I do seem to recall that not every film camera used 35mm film. There were large format cameras all the way down to 110 film and probably smaller (though the smaller films were rarely if ever used with interchangeable lenses.

jeshaw2 Loc: Ohio

This becomes important in making a panorama photo. Here, one needs to make several adjacent but overlapping shots of the scene so the stitching software can line things up. One needs to correctly calculate the overlap area and resulting pan angle between each shot. The crop factor is a part of that calculation.

Jim Shaw

Morning Star Loc: West coast, North of the 49th N.

Calculations... and I don't even like math. The odd time that I do a pano, usually 3 - 5 shots, I take the pictures on the fly.
On the first shot, I pay attendion to top and bottom edges, especially on the right-hand side, in the viewfinder. Also have a look at what part (pole, roof, person, tranctor) is about 1/3 in from the right side.
On the next shot, I make sure that the top and bottom are in about the same place in the viewfinder, and the item is now or against the left edge of the image. Exposure, f/stop, focus are all manually set, usually to the part of the image that is going to be the centre of the finished pano.
I pay no attention whatsoever to what the crop factor is, just use what I see in the viewfinder. Has worked well for me so far.

GoofyNewfie Loc: Kansas City

I've never needed to calculate the focal length for stitching panos.
What program are you using?

boberic Loc: Quiet Corner, Connecticut. Ex long Islander

Perhaps so but computers today offer a quantum leap in RAM etc and features, and are much less expensive than computers 20 years ago.

amehta Loc: Boston

And cameras today offer a quantum leap in megapixels, high ISO performance, and other features, and are much less expensive than cameras 10 years ago. In some cases, they're basically free, in our cell phones.

jeshaw2 Loc: Ohio

On a bright day, I can not see the image in my LCD screen and 'hoods' don't help much. Therefor, I do my work 'by the numbers'. I also try to make things easy for my post software so it makes fewer stitching errors.

The 'focal length' is not calculated; it is just used in the angle of view calculations (horizontal &vertical). That is unless you are referring to the need to adjust for the DX crop factor; e.g. a 50mm lens on a DX sensor is 50 * 1.5 = 75mm. Some programs ask for a corrected focal length, others ask for sensor size. I do my calculations in MS/EXCEL so that I can set the detentes in my pan head correctly and determine the number of shots needed for a given pan angle.

Of course, it is not 'mandatory' to calculate anything for a pan shot.:D One simply applies the amount of rigor they desire in their work.8-) Speaking of 'rigor', I also take measures to resolve parallax issues in camera also; but that's another topic.

HTH
Jim

dynaquest1 Loc: Austin, Texas

Cool....and if you leave your camera (assume you have a DSLR) in Auto or Program modes you don't even have to understand aperture, shutter speed or ISO either. :-D

jeshaw2 Loc: Ohio

Touche' pussy cat! :thumbup:

Whuff Loc: Marshalltown, Iowa

Thank you. Finally an explanation that makes some sense. I've seen this topic debated here numerous times and didn't have a clue as to how it would would ever translate to taking photos. I appreciate your taking time to give a plausible reason why anyone would be concerned with it.

georgevedwards Loc: Essex, Maryland.

I think the answer, by looking at the diagram, is that is the field of view, not the zoom which is changed. I got a full frame lens for my cropped sensor camera and was told it makes like a portrait lens now, from 55mm to 80mm. Then I read a good article which pointed out this is rather false, the good portrait lens (80mm) means you can stand back and not get distortion of the nose and ears from being close. However, although the crop sensor makes the face look bigger in the frame the distortion is still the same, so it is a false claim, said the article, and I think after examining the evidence given it is true.

amehta Loc: Boston

A number of times in the past few months, people have asked for help in getting pictures of groups, with the main thing that they new was the number of people and the basic room that would be used, so there were some limits to how far back they could go. They wanted to know what lens they should use, at least one was open to renting a lens. None was a pro, but they were "the photographer" in the group, and obviously wanted to do a good job. Having a sense of the field of view for different focal lengths helped determine the lenses which would work well.

For a second reason why this matters, things get more complicated. The "first step" of photography is thinking about your subject. A "second step" is thinking about the background. Let's say you have a 24-70mm zoom and a full frame camera, and you want to take a picture of a person. At 24mm, the angle of view is 84°, at 70mm it is 34°. At about a 3 feet away, at 24mm you fit the entire person in the picture. If you move back to 10 feet, you can fit the person in at 70mm. Now let's say they are standing on the sidewalk in front of a building. Which you do, 24mm/3 feet or 70mm/10 feet, will decide how much of the building you get in the frame. You don't have to worry about the details of the calculation, but when you want to fit different things in the image like this, understanding that wide-angle and telephoto will give different results like this at least lets you know which way to try things.

pecohen Loc: Central Maine

I have a closely related question. For a lens sold for a specific digital camera, is the advertised focal length the actual focal length of the lens or is it adjusted to be the effective focal length relative to a 35mm camera?

I ask this because of an experiment I performed recently. I wanted to see whether it was worthwhile to buy an older, used telephoto lens to use on my Nikon J1 camera using a T1 or F mount. Of course this means using the camera in manual mode, but I wanted to see how inconvenient that actually is. I found an old 100mm - 200mm lens on eBay for $10, and an adapter for another $10 and tried it out. Focusing at infinity made that part easy and I found the manual exposure not particularly hard either.

What surprised me, however, is that the field of view at 200 mm was almost exactly what I got with the J1 lens set at 100mm with a 2X extension on it (the quality was about the same too). The only way this makes sense to me is if the kit lens for the J1 that Nikon describes as a 30mm - 110mm lens really does not have those focal lengths (these must be the adjusted focal lengths). With an adjustment factor of 2.7, the true focal lengths must be from 11mm - 41mm.

amehta Loc: Boston

The Nikon website page for the 1 NIKKOR VR 30-110mm f/3.8-5.6 (link) says "the 30-110mm (picture angle equivalent of an 81-297mm in 35mm format)," so 30-110mm is the actual focal length.

If you combine it with a 2x extension, the actual focal length is 60-220mm, so that should be comparable to the 100-200mm lens.