Lightnings taking a ride

by ceinmart

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1

Absolutely, there is a drop in quality as the zoom-ratio increases. This is normal because the designers have to made compromises when placing lens elements. This gives a performance which is uneven too. Many times you can have decent sharpness at one end of the zoom and it will truly terrible at the other end or somewhere in the middle. The other thing is ...


0

Pentax 50mm has the nicest bokeh and sharpness I've ever see... I think you've answered your question. Stick with image quality over anything else. You can always make up for other deficiencies with skill and technique. Shoot for best image quality.


1

If you are going to make mostly portraits, a 50mm prime would fit you much better. Not only gives you a lower aperture, but the image quality is better with primes. Don't worry about the "ideal" 70-90mm range, 50mm is a classic focal length for portraits.


0

Unfortunately for you, the DSC-H20 is a zoom camera with a focal length that varies from 6.3 to 63 mm (or 38 to 380 mm if you're using to thinking in terms of 35 mm film). Unless you've got the EXIF data for the images you're looking at, I suspect you're probably stuck here.


1

Let's go for a "purely" mathematical reasoning. Let's assume that the eye has a FOV = afov. With ho an object height and hs the sensor height, d the distance to the object and f the focal length, you have the following schema : Finding a relation between all those values is straightforward : hs / f = tan(0.5* afov) Unless I'm mistaken, you "just" have ...


0

Use 50mm if you want to separate the person from the bacground, you can always crop the image to simulate the 70mm (at 8Mpix) or 90mm (at 5Mpix). To include enviroment use 17-50/2.8 at smaller focus distances. And take telezoom for larger distances. You may found usefull to experiment with http://camerasim.com/apps/camera-simulator/


0

(I am teasing you:) You seem to be seeking a hard rule that you can apply without thinking, but there are no hard rules, certainly no One rule, and thinking is always helpful. :) It always depends, on the situation, and on what result you want. 70-90 mm is "ideal", if assuming a cropped APS sensor, and assuming a normal subject distance of at least 6 to ...


0

I will just do some math (I will avoid all the sharpness of the lens and noise things aside). 12 Mpx = 2829 x 4243 px 24 Mpx = 4000 x 6000 px If I divide 4000/2829 I get a 1.414 ratio This means If I crop a photo, taken with a 50mm lens on a 24Mpx camera to a size equivalent of a 12Mpx photo (in pixels) will look as If I had photographed that with a 70mm ...


0

More "reach" with the same lens is "achieved" with a smaller sensor (DX), which is simply a crop, but it has to be enlarged more, which is a telephoto effect ("reach"). You can easily see this in your editor, just zoom any image larger, which shows as a crop, which is enlarged more. Same visual effect as zooming with a telephoto lens (except lens zoom could ...


1

It will give you some cropping room - if you use the same lens and a couple of steps back. If you're already stood against the back wall of your studio then more pixels won't help you. 12-24Mp also isn't as big a jump as you might first think. If you're using the extra pixels as a lever to get someone to break out their wallet then you might have to try ...


0

It also depends on how much background do you want to keep. With the Pentax prime or Tamron zoom lens, you'll get a better background separation, in addition to having more backdrop behind your subject. This will arguably be nicer as the bokeh effect will be more apparent (more concentric circles, soft focus etc.). On the other hand, if you want to get ...


5

Yes, and that is the maybe the major advantage of high-resoluton sensors, for typical print sizes. You can crop the image and still get an image with reasonable detail. That said, the actual resolution of the image depends on the quality of the lens, too. Only quite high-end lenses will actually make good use of a 24MP sensor. if you look at a lens ...


0

I think that taking a head and shoulders picture with a 50mm lens means that you have to get too close for your subject's comfort and in addition risk some distortion. I've always used 90mm prime lenses with as fast an apeture as my bank balance will permit. As usual with photography, it's a trade off - it's a great lens but I have to move around a good ...


0

Although designs vary on a lens by lens basis, lenses that allow you to endlessly move the focus ring use a design that allows the focus ring to slip when the end of travel of the lens' focus element is reached. This is most often seen in lenses that use a ring type focus motor that drives the focus element using very high frequency electrical pulses rather ...


0

Well, why not just put your 70-200mm lens on and zoom until the image on your lcd is the same size as your eye view without the camera. The lens will then read what focal length your at. Or just use the view finder. Close study of actual view, LCD view and Viewfinder view will get you there but you will need a tripod and at least 10 minutes. You may find ...


0

I just did some test shots with my Canon FX50 and my Sony F3 with 55-210mm lens Here are the results - read from Bridge: Sony: F3 with 55-210mm Started at 55 mm - Bridge shows 55m - focal length in 35mm = 82mm F3 with 55-210mm full zoom at 210mm - Bridge shows 210mm - focal length in 35mm = 315mm Shows lens as 55-210mm Canon FX 50 (50 times zoom) No zoom ...


3

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 other characteristics that are preferable, like having a reasonable focus range. If you add extension tubes between the lens and the camera, the minimum focal ...


10

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 focus distances depending on which factors the lens designer chose to optimise.


1

I know it's an old thread, but this question seems to come up now and then. FWIW, I added a calculator to compute an object distance in an image. http://www.scantips.com/lights/subjectdistance.html You will still have to know your values to make it work, one of which is approximate real height of the object. Discussed there.


1

Your B&H link gives the link to the camera user manual, and its spec sections says: Lens: ZEISS Vario-Tessar Lens 27× (Optical), 54× (Clear Image Zoom, while recording movies) 320× (Digital) F1.9 - F4.0 Focal length: f=2.1 mm - 57.0 mm (3/32 in. - 2 1/4 in.) When converted to a 35 mm still camera For movies: 29.8 mm - 1609.2mm (1 3/16 in. - 63 3/8 ...


0

A back-of-the-envelope calculation based on field-of-view calculators and the known size of the moon, and the ratio of 125:4000 vertical portion of the frame, indicate that 55mm is the right ballpark. Testing (CR2 processed by Adobe DNG Conveeter) shows that the lens indicates specific marks only, e.g. 55 then 60, not a continuous measurement. I verified ...



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