10

You appear to be seeking to maximize the amount of background blur. Factors that increase background blur are: Distance to subject (closer) Distance to background (farther) Focal length (longer) Aperture (larger opening; smaller F-number). Sensor size in and of itself is not a factor. However, it influences focal length choice and working distances. ...


10

It is typically called "lens compression," where things farther away appear nearer to the subject/closer together. And the opposite of this is typically called "lens distortion," where something closer to the camera appears larger than it should... like someone's nose in a portrait. Neither effect actually has anything to do with the lens,...


7

You can't stop the EF 20-35mm f/3.5-4.5 down to f/3.5. That is because f/3.5 is the f-number when the aperture is wide open and not stopped down at all. It can only open up to f/3.5 with the lens' focal length set to between 20mm and 23mm. I'm going to take a wild guess and assume that you're trying to get the lens to open up to f/3.5 at a focal length ...


7

Neither the focal length of the lens nor the aperture of the lens change if we change the size of the sensor. What does change is the angle of view and the depth of field, but not the exposure. (We are assuming neither the focal length, f-number, the camera position, nor the focus distance to our subject changes - only the size of our camera's sensor.) We ...


6

Long focal lengths (ie, high zoom factors) tend to remove depth because as the camera is far away, everything is shot from the same angle and this removes perspective. But is is really the distance that does it, cropping a picture taken with a shorter lens (but from the same place) would yield the same result.


5

Because in the Nikon D3x00 and D5x00 series, as well as many previous entry level Nikon DSLRS and pretty much all Nikon 35mm film SLRs, the same mechanical motion actuates the mirror assembly and the aperture linkage. Once the mirror is up, the aperture can not be changed from the body. This worked fine when the mirror was always down until just before a ...


5

The earliest investigation of the right constant c that I am aware of is Petzval's 1859 On the camera obscura. The paper is predominantly about a new lens design he has created but he begins with an investigation of the optimum radius of a pinhole for resolution of the image. Resolution is defined as the ability to discern the difference of two very close ...


4

The f/2.8 in the name of the lens does not indicate fixed aperture in the sense of not being able to change it - it designates the widest aperture. You should still be able to set it to e.g. f/4 or f/8, but you won't be able to set it to f/2, because the maximum is f/2.8. The sense in which it is "fixed" is that you can use f/2.8 throughout the ...


4

Flat light. That is, light that is either from behind the camera and very close to parallel to the lens' optical axis (such as an on-camera flash) or extremely well diffused such as on an overcast day. Smaller apertures (larger f-numbers) combined with longer focal lengths that force shooting from further away to get the same framing will tend to "...


3

f/4.5 doesn't mean that the hole in the iris is physically 1/4.5 times the focal length. It means that the size of the image of the hole, as viewed from the front of the lens through the lens elements in front of it, is 1/4.5 times the focal length. The image of the hole is the entrance pupil. If you can, look at the image of the hole from the front as you ...


3

All recent Nikon entry level DSLR cameras, (including the most recent D3500 and D5600) have the option to display the aperture being used as a graphic display. Other Nikon cameras may also have this option. Here is page 208 of the D3500 manual which shows you how to choose this option. Canon entry level cameras have something similar called “Guided Mode”, ...


3

Different lenses have different behaviours, but as a rule of thumb: if you need maximum sharpness in the center but don't care about corners (for example you are shooting a portrait with shallow DoF), set your aperture to one step higher than lowest available. If you need sharpness across whole frame (typical landscape) start with f/8 and adjust as necessary ...


3

I am looking for such lenses as well. In general putting the aperture at the front or outside is avoided because not good; best is to put the aperture more or less in the center of the objective. With the aperture in front you'll have more aberrations and/or need bigger and more expensive design. Only in two cases the front aperture design is used: if the ...


3

Yes. That is to be expected. I cannot find the noise to be exceptional in any way. Any tap on the focus button, or any release would pretty much do the same. Note that the focus and aperture behavior on many Sony cams differ from AF-C to AF-S. AF-S always opens up the aperture and then steps down to the set aperture to make AF in low light more precise. ...


2

Whether shooting stills or video, the classic solution to being able to use a wide aperture in bright light is to use a neutral density filter. Particularly with dedicated video cameras, where very short exposure times make the video look "choppy", advanced cameras usually have built-in ND filters. When using so-called "hybrid" cameras ...


2

This sounds like a hardware issue, it's likely that the shutter wheel is damaged. If you have recently purchased the item, I'd recommend requesting a refund. I would not recommend attempting to repair an issue like this yourself unless you are okay with destroying the camera or really know what you’re doing. You could try a factory reset the camera software ...


2

Maybe a more practical way to determine the T-Stop of a lens?: Arrange a uniformly lit white surface big enough to cover the FOV of a lens. Use your camera with fixed shutter speed (M-Mode), ISO, WB etcerera to make an exposure of the surface without a lens. Put the lens on the same camera with the same settings, and make a second exposure of the surface. ...


2

If a lens has a fixed aperture you cannot change it. But such lenses aren't very common for interchangeable lens cameras. The most common lens of this type would be a "mirror lens", and these are usually fixed at f/5.6 or f/8 for focal lengths around 500-800mm. If your lens has a maximum aperture of f/2.8, you almost certainly have a constant ...


1

TL;DR: You can't make a large lens to increase the brightness, but you can increase your depth of field by focusing at or beyond the hyperfocal distance. You didn't say what you were photographing, but with anthotype, cyanotype, etc., I imagine you're probably just trying to get basic photos of mostly static things. Landscapes/cityscapes, pictures of ...


1

No. The aperture number determines the ratio between light emitted and light captured. The more light you capture, the more angles of the emitted light you need to catch and different angles only converge in the focusing plane. You can warp the focusing plane to better fit the subject (full-frame cameras and tilt-shift lenses do this), but the more light ...


1

If all of the magnification takes place between the front of the lens and the physical aperture when you zoom, then the entrance pupil, which is the effective aperture that is actually used to calculate f-number, also grows by the same ratio as the focal length. As you zoom to longer focal lengths the size of the aperture as it appears through the front of ...


1

As you know, the focal ratio (f-number) is calculated by dividing the working focal length by the working iris diameter. Therefore, these fundamental values are intertwined as to their influence on image brightness (exposure settings). The bottom line, as you zoom, image brightness rises an falls significantly. In fact, double or halving the focal length ...


1

The only way to know the effect of aperture shape is make a picture, then look at it. With practice, you may have enough experience to make accurate predictions before making the picture, but “try it and see” experiments will always be necessary. Experiment is part of photography and most experiments fail. The aperture shape will always have some effect on ...


1

Optically, a long lens is said to compress perspective. When a longer focal-length is used, the relative distance between scene elements is shorter. You can visually play with the concept using the Nikon Lens Simulator. In it, choose a lens which a high zoom ration, say a 28-300mm and play with the zoom slider. You will see the scene looking flatter as you ...


1

After doing some research (this thread being a particularly useful one: https://www.dpreview.com/forums/thread/4392551), it seems that certain Sigma lenses are incompatible with newer Canon models like the M50. You'll either have to wait for a firmware update (if they offer one), sell the lens, or wait until you get a new body (check to make sure it works ...


1

The terminology in your question is most likely incorrect. Several manufacturers make a 16-35mm F/2.8 lens which is a Constant-Aperture Zoom meaning that its has the same maximum aperture at any focal-length. This means you can set it to F/2.8 at 16mm and 35mm or any focal-length in between. You can also stop it down at any focal-length. Most, if not all, ...


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