27

Stopping down is suggested because many lenses are considerably less sharp when wide open. This does not change on a crop-camera, since it is a property of the lens. There is however for most lenses a difference between center sharpness and corner sharpness. Most of the time, the center sharpness is substantially better than the corner sharpness. The ...


15

EV is a measure of illuminance, which is defined in the link you provided as "luminous flux incident on a surface, per unit area". You are correct in stating that when if you keep field of view, depth of field and subject brightness constant: Ev_crop = Ev_ff x c² however since: Area_crop = Area_ff / c² and Light(total) = EV x Area we arrive at ...


15

When I started photography, this one took me ages to figure out, because people tend to explain it with a lot of math, or in a way that makes sense once you already grasp the principle but not before. How does crop factor affect perspective? It doesn't. Not at all, in the slightest. The only way you change perspective is to move the camera. Changing ...


13

Any EF fit lenses you own (usually marked with a red dot near the EOS mount) will work fine with the 5D mkII Any EF-S fit lenses you own (usually marked with a white square near the EOS mount) won't work or fit the 5d mkII, as these are designed to fit crop sensor cameras like the T2i and not full frame sensors like the 5D mkII As an addition, some non-...


13

You would actually get at-par to somewhat better image quality using this lens on your cropped sensor, than using a lens designed for crop sensors, in some aspects: You would get rid of most of the vignette, as the DX cropped sensor is effectively stopped down 1.23 stops compared to full-frame. (ref. Wikipedia). Thus, from the review link you provided, the ...


13

From the "Recommended For" tab of the Tamron web page for that lens: Tamron Di-II lenses are engineered expressly for digital SLR cameras with image sensors commonly referred to as APS-C, measuring approximately 24mm x 16mm. This means the image circle is sized for the smaller APS-C sensor, and is too small for a full-frame camera like the 6D. This is ...


13

Crop factor has nothing to do with T-stop. T-stop is strictly about light transmission which affects exposure. If a lens could be 100% transmissive the T-stop and f-number of the lens would be the same number, but they would still be measures of different things. T-stop measures how much light is passed through the lens, f-stop measures the size of the ...


12

The difference between the EF 50mm f/1.8 II and the EF-S 18-135mm f/3.5-5.6 IS is not in terms of focal length or angle of view provided by each lens when both are used on an APS-C body. What makes the EF-S lens different is that the image circle projected by that lens is smaller than the image circle projected by the EF lens. The EF lens must project a ...


11

It's quite simple: A lens projects what is called an "image circle" onto the sensor. A DX-only lens is designed to project an image circle just big enough to cover that sensor. An FX lens is designed to project an image circle big enough to cover a FX frame. Therefore an FX lens will work on a DX sensor properly. (But it will have an effective "crop ...


10

Here are a couple of different common paths you could go that are sub-$1000. But as everyone is telling you, usage is the easiest way to narrow down your choices to something you actually need, rather than something you just want. The easiest way to really start considering an "upgrade" from the kit lens is to consider in what ways the kit lens frustrates ...


10

All else being equal, yes. A bigger sensor requires more power. Advancement in power-saving technologies can sometimes improve that but with higher pixel counts being the norm, we do not see much of that. Each pixel requires circuitry so higher megapixels require more power than making the sensor bigger. Luckily bigger cameras have room for bigger ...


10

The crop will eliminate anything that happens outside of the sensor area. At worst you'll lose the worst of the vignetting, at best you'll lose all of it. Because the worst of the barrel distortion is right in the middle of the sensor, you're going to be getting all of it. (Edit: Anindo Ghosh correctly points out in his answer that the edges are actually ...


10

I would choose the 7D for a few reasons: The effective maximum aperture of the 5D Mark II combo will be f/5.6 X 1.4 = 7.84, nearly f/8. This will somewhat cancel out the light-gathering advantage of the full frame camera. You will still have a bit less effective reach with the full-frame camera, even considering the small pixel-count difference and even ...


10

Perspective is determined by one thing and one thing only: Subject distance. Period. If you took an image using a rectilinear wide angle lens such as 17mm, which yields a diagonal angle of view of 104° on a full frame/35mm camera and cropped the resulting image so that only the center 3.08333° is in view, you would have the exact same perspective as if you ...


9

Foreshorntening (the technical term for the effect of "flattening" objects) is determined by subject distance only, not focal length. When using a wide angle lens if you are the same distance from your subject as you would be when shooting with a portrait lens, you'll get the same flattering effect, only your subject will take up less of the image. A crop (...


9

I believe F1.4 is the best you can do on a compact so far: http://www.dpreview.com/news/2012/7/18/Panasonic-announces-Lumix-DMC-LX7-with-F1-4-2-3-24-90mm-lens You know from 35mm format lenses that it is hard to find those that are sharp wide open. it is hard to get all those rays of light to hit a single small dot. On a compact sensor, those dots are even ...


9

The amount of light passed through the lens stays the same, the lens will still be a F/2.8 lens. Since the smaller sensor only crops out a different area from the illuminated circle, the exposure related properties of the image taking process will stay the same, regardless of the crop-factor.


9

In general cameras do use darker materials to construct light boxes and the interior surfaces of lenses. Many also use materials, such as the flocking material found on the inner surface of higher end lens hoods or plastic that is molded with a textured surface, that scatter what little light is reflected. Even when using a camera with a full frame sensor a ...


8

On some lenses the image circle does indeed get bigger as you zoom. I know from experience the Canon EF-S 10-22 f/3.5-4.5 does this. At 12mm the image circle is big enough for a 1.3x crop APS-H sized sensor and by 15mm it is big enough for a full frame 35mm sensor. However lenses such as the EF-S 17-55 f/2.8 vignette at all focal lengths on full frame. I ...


8

You can get more lens flare using a full frame lens on a smaller sensor when shooting close to the sun or other lightsources. The reason for this is simply the APS-C lens has a narrower field of view and so a lightsource just out of frame has no physical path through the lens. If you're using a full frame lens with the same composition then there is a path ...


8

You will crop away the outer edge of the image and this will cause you to lose the highly distorted edges of the photo. this is particularly obvious when you are dealing with a very very wide angle where normally a circular image would be seen but due to the crop you see a square image. This review of the Canon 8-15mm fisheye contains a picture how the ...


8

The same light will pass through the lens regardless of the type of camera to which it is attached. Less of that total amount of light will land on the smaller sensor. But exposure, when discussed in terms of varying sensor/film sizes, is not about the total amount of light falling on the sensor. It is about field density, or the amount of light falling on ...


8

You can't. What we refer to as equivalence is only an approximation. You can't put a different lens on a crop sensor camera and get the same shot with the same field of view from the same shooting position with the same depth of field using the same ISO and the same shutter time as you can get with a full frame camera. The converse is also just as true. You ...


8

Lens produces circular image (image circle), which projected on rectangular matrix. So question is not only about full frame lens on a crop sensor. AFAIK black box (mirror box) is specifically covered in material that absorbs light well. I remeber that in older cameras (my film Nikon F90) this space is covered in fuzzy (furry?) material so that light ...


7

Does sensor size affect lens distortion? Short answer: Yes. The reason is only because most if not all distortion happens on the edges of the lens glass. Using a cropped sensor is indeed like printing off a 8x10 picture and then cutting out the 4x6. and therefore by trimming the edges you will most likely get rid of some of the distortion. Just to ...


7

The DOF will increase, but not entirely with the crop factor, however, I just learned that it converges to that in certain cases. Your distance increases by the crop factor, but the DOF doesn't follow a linear curve, which means that the increase on DOF as a factor depends on the distance you start at. An important factor is Circle of Confusion which is ...


7

Here's the short answer: a wide angle lens on a crop sensor skews the image exactly in the way it does in the center of the frame on a full-frame sensor. In turn, this means that using a wide angle lens (small focal length) on a crop sensor gives the same perspective distortion as using a narrower lens (larger focal length) on a full frame sensor, with the ...


7

Your logic is sound. If your assumptions were right, then your conclusion would be right. Let me turn one of your questions around. You ask: Why does crop factor apply with APS-C-lenses, while it sounds like the image circle is compressed onto the APS-C-sensor (thus making a wider FOV)? In fact, the image circle isn't compressed, and does not make a ...


7

The Canon extenders will not physically mount to an EF-S lens. Even if you defeat the keying the front part of the EF 2X (any of the three successive versions) would extend into the rear of the EF-S 55-250mm and almost surely contact and damage the rear lens element or the front element of the extender or both, at least at certain focal length and focus ...


7

If you take a photo of a FF camera and 75mm DX lens and compare that image with another shot of same subject made by a cropped camera and a 50mm lens what you will see ? But to be able to see the "same subject size" in the pictures, the longer lens must stand back further. So that is a difference in what the lens will see there, at that new location. So ...


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