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1

Angle of view is determined by (real) focal length and sensor/film size. That's your starting point. AoV=2*arctan(d/2f) where: AoV is the Angle of View d is the size of the sensor/film in the direction measured f is focal length (in the same units as d) For a circular hood you would use the diagonal measure of the sensor/film For a "petal" hood ...


1

"Internal focusing" is the term for that and it is rather common. Certainly a lot more so than "internal zooming" which makes a lens bulkier for transport and thus is comparatively rare for large zoom ranges. Off the cuff I remember the Panasonic DMC-FZ50 as a superzoom camera with both internal focusing and zooming. To have either ...


3

A lens such as the Canon 18-200mm only makes sense if the convenience of only one lens is more important to you than pretty much all optical performance factors as well as the performance/price ratio. Overall you'll get lower optical quality and pay a premium for the privilege. In order to get such a wide range of focal lengths in a single lens you give up ...


2

This may not fully answer the question, but there are a few videos on youtube that compare the RF equivalent against the EF to see the difference. Canon RF vs EF Lenses - Which are the Best? | Comparative Review by BorrowLenses In the video he talks about the flange distance and that in RF-lenses the sensor is closer to the glass, which means eliminating the ...


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Following up on my bird feeder comment I took some quick shots to show roughly what this looks like. Our feeder is 20 feet (6m) away from where I would shoot from. I find I prefer shots where the birds are in the trees on the way in to the feeder or the way out. The photo was shot at 200mm on an APS-C sensor from about 25 feet (8m). It is a chestnut-...


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If you look at a pinout diagram of an a-mount lens, it shows that there are, among others, "focusing motor power" (so, a non-logic-level power bus), logic power, and logic pins that are (from camera body perspective) logic outputs. If any of these got shorted together, there would be at least a theoretical risk of camera body damage - shorting any ...


3

The best way to inhibit the growth of fungi in lenses that have already been infested and cleaned is to periodically expose the internal lens elements to UV radiation. This can be as simple as regularly exposing them to sunlight for a few hours, or as complicated as buying a dedicated UV light to shine through them. Enough UV light in sunlight reaches the ...


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It's all about etendue. The maximum amount of light available for an exposure is determined by the system etendue, which defines how spread out the light is. Etendue is defined by the angular extent (apparent/relative size) of the source/subject as seen by the objective element. And it is simultaneously/equally the angular extent of the objective element as ...


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The transition is not as smooth as the calculations may indicate. In the real world there is a disrupting factor known as reciprocal failure ! Which adversely affects the outcome , it reduces the expected amount of light transferable a factor dependent to some extent on the nature of the glass used. Coating the lens and treating the coating with various ...


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I can't recommend the EF 75-300mm f/4-5.6 III to anyone. It's probably the weakest lens in Canon's entire catalog. It's at the softest at the longest focal length of 300mm. A wide zoom range lens like the 18-200mm also comes with compromises in optical quality and maximum aperture in order to allow it to have such a wide focal length range. An 18-55mm + 55-...


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Your question is whether you should go for "a 75-300mm zoom lens or a 18-200mm zoom lens." You have short-listed these two kinds, based on your budget, I presume. Therefore, without describing the advantages of going for other more expensive or specialized lenses, let me give you a straight-forward and simple answer. [When someone asks for a drink, ...


3

Straight up, I should mention that I am not a bird photographer and do not have much experience in this area. Hopefully someone with more experience can offer an answer with more specifics. Preferred Zoom Range However, the bird photographers that I know all seem to gravitate toward use of 150-600mm zoom lenses (that ... and techniques to allow them to get ...


3

Ignoring the specific lenses here, the question you're really asking is "which is better, a general purpose 'superzoom' lens or a dedicated telephoto lens?" The answer to that is of course "they're different": The superzoom lens (18-200 in your case) has the advantage that it has a very wide focal length range; it can do everything from ...


1

The angle of vision isn't everything. If your camera sensor doesn't receive enough IR, changing the angle of vision will not change that. The important factor is the "aperture" of the lens, usually noted as f/3.0. The smaller the number the more light the lens can collect. A f/2.8 lens collects twice the light of a f/4.0 one ((4/2.8) squared is ...


1

The lenses used in VR headsets are for focusing on the screen. It is similar to wearing glasses. It is also similar to the lens in the viewfinder of a camera which has adjustable strength for people with different eyesight. These focusing lenses do not affect the system FOV; unlike a camera lens where the focal length/magnification strength does affect the ...


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Is this because people who've reviewed these lenses have higher expectations for a 24‑70mm f/2.8 lens than they do for a 24‑105mm f/4? There's more than just a bit of something to that. There's also probably a little more going on that has to do with those who regularly use 24-105mm f/4 lenses and find them useful tend to have lower standards in terms of ...


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As a formar long time Canon 700D user that did wildlife and amateur sport photography with some of the lenses that you listed as your options i recomend you go with the 200mm f2.8.. it is a prime lens, its much sharper than zoom lenses and also lets in more light due to the f2.8 aperature... I used the sam combo (700D + Cnaon 200mm f2.8 and 1.4x) ...


3

StackExchange usually tries to avoid questions and answers that are subjective and tend to generate opinion ... so I'll try to respond by discussing attributes that tend to be good for portrait photography. Near the end I'll discuss the trade-offs of the lenses you asked about. I wouldn't necessarily limit yourself to just these two choices. Also keep in ...


1

The biggest reason many folks who use an f/2.8 lens for landscapes shot at f/8 do so is because they already have an f/2.8 lens anyway for when they need f/2.8 in other shooting scenarios. It is generally true (though there are always exceptions) that f/2.8 zoom lenses are built more robustly than narrower, variable aperture lenses. Thus they can withstand a ...


1

Definitely the better lens is better! The real question is whether the difference is important to you. Even though the slower lens gets sharper when stopped down it never becomes as sharp as the 24-70mm F/2.8 wide open and the difference becomes even more significant with the F/2.8 stopped down. Sharpness would be the first reason. While lens sharpness can ...


2

After returning that lens and buying the new one, I can conclude with confidence that the first lens was definitely defective. This new lens is not perfect either, but it performs much better. You can see those ghosting flares are going up and a bit to left, but the effect is less noticeable. The focus on both images is the best I could get - at infinity. ...


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