Serene Life

by garik

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0

Mr.Grum offered some very good reasons why faster lenses exist - because of fast and reliable focusing, and of easier framing and following due to brighter viewfinder. To add a little to what he said, focusing with teleconverters is much better too when the lens is fast. Apart from focusing, optics in slower lenses often is not designed to be used with a ...


0

Usually, but not always, the fastest lenses 180mm and longer are apochromats. This is seldom the case with slower lenses, but there are exceptions. Slower lenses generally don't require the extra correction of the apochromatic design. Examples of the latter are the 180mm Elmar-R made by Leica in the 1970s to 1990s. This f/4 lens is very light and compact; ...


2

With DSLRs the lens is wide open until you take the shot (at which point the iris quickly closes). Having a faster lens therefore means you get a brighter viewfinder image. It also means the AF system can use a wider baseline which in many bodies activates more accurate AF sensors.


1

Some have told me the f/2.8 lens requires more glass to achieve f/2.8 and therefore it lets in more light and can shoot at a faster shutter speed at the same aperture - but I really don't think that makes sense. Basically incorrect. The entrance pupil for 300mm at f/8 will be 37.5mm in diameter, regardless of the diameter of the lens' front element. So ...


1

Why not use millimeters to measure the aperture size? Why do we even bother with this system? Because physics: http://imagine.gsfc.nasa.gov/YBA/M31-velocity/1overR2-more.html Let's say we used millimeters to measure the aperture instead. You compose your shot, meter your scene and choose your settings. If you decide to zoom in, changing the focal length ...


2

Modern automatic SLRs / DSLRs adjust the aperture in exactly the same way as manual SLRs, by closing the iris blades in the lens. The only difference is that it is closed/opened using an electric motor and this happens extremely quickly when firing the shutter, so you are probably unable to see it with the naked eye.


2

You've pretty much figured out your three options. (Something else). f/2.8 zooms are the preferred choice for many event-shooting professionals for the reasons you state. So, this is probably the most effective route, but also the most expensive. Flash (and many pros will do this in combination with f/2.8 zooms) can also help immeasurably with this type ...


0

We ran into the same type of issues with our indoor shoots. We ended up getting a "faster" variable lens, f2.8 17-55, and that has helped. Also getting a lens with IS (image stabilization) can help reduce vibrations and allow for slower shutter speeds, as long as your subject isn't moving too much. A decent flash is also an extremely valuable tool. ...


0

I had a similar problem a few years back and I purchased the Tamron SP AF17-50mm F/2.8 XR VC Di II LD Aspherical (IF) (Canon Mount) for £346 in UK. The extra stops really helped me at ISO 1000 and less. I also developed a new style of holding the camera indoors. I would bring my left arm across my face and rest the hand on my Right Shoulder creating a rigid ...


7

This isn't a problem at all. The behaviour of the camera is normal. When the aperture is adjusted on the camera (eiter automatically or manually) the aperture of the lens wont change untill the moment when you take the shot. The reason to design the camera in this way is to maximize the available light (and microcontrast between out-of-focus and in focus ...


0

But if I use an f-stop that is high enough to blur the background, my shutter speed only goes up to 1/250s, which produces overexposure. Flash photography is a little different in that you can't use the shutter speed to control the amount of light due to the flash. That's because the duration of the flash at full power is typically around 1/250 sec., ...


0

Not exactly sure of your setup, but they sell diffusers that attach to the flash. The quickest way, however, is to aim the flash at a light colored wall or ceiling instead of directly at the subject. Here is an example. Not only will it reduce the flash intensity, but it also softens and can often eliminate shadows. It is a good all around technique that ...


1

I've been exploring use of flash for the first time myself, using 50mm f1.8 lens. For me I get best results in camera manual mode (pick shutter speed and aperture), and then fine-tuning my flash's manual settings (i.e. for camera settings I leave them stable, and just tinker with the flash). For example - I find flash power 1/16 and zoom 105mm gives really ...


3

How do I calculate the aperture size and area You divide the focal length by the aperture/F-stop value. Infact, that's what the F-stop/aperture value is. It's a divider. Sometimes written as ƒ2.8 (as an example) but a lot of people leave out the vinculum and should be written as ƒ/2.8. Replace the ƒ with the focal length and that's the diameter of the ...


2

Your lens is a 35/2.8, but that doesn't mean the aperture is necessarily f/2.8. Just that f/2.8 is the widest it can be opened. The f-number is the focal length divided by the aperture diameter: f_number = focal_length / diameter So, solving for the diameter: diameter = focal_length/f_number. So, in this case your diameter is 35mm/2.8 = 12.5mm. If the ...


2

The aperture size is a property of the lens only and does not depend on the crop factor. It does depend, however, on the actual focal length of the lens (not the "equivalent" focal length). So you need to obtain the actual focal length by dividing by the crop factor. You can then calculate the size (diameter) of the aperture (strictly speaking the size of ...


2

You can image a red laser across the room shining on your pinhole, and measure the diameter (in pixels) of your first dark ring (if your pinhole is a clean circle). Then knowing pinhole-to-detector distance and the formula for the angular diameter of that first dark ring (about 2.44 * wavelength / pinhole_diameter, in radians) figure out your pinhole ...


0

I'm not so sure that landscapes are usually taken with "big" apertures. However, there is a reason large apertures make sense in some situations. When there is nothing close to the camera in the picture, as can be the case with landscape shots, most of the scene will be at infinity focus. In that case there is no benefit from a larger depth of field, so ...


2

Most of the time, a "big" f-number is recommended for landscape photography. But a high f-number such as f/16 or f/22, when dealing with APS-C or FF cameras, means a very narrow or small aperture. The large aperture is at the other end of the scale at f/1.4 or f/2. See What is aperture, and how does it affect my photographs?


7

You didn't explain where you read this, or what the meaning of "big aperture" means to you - so I'll explain. Certainly you can shoot landscape photography at whatever aperture you wish. Shooting with a wide open aperture is not the most common aperture selection for most landscape photography though. By wide open, I of course mean a wide aperture such as ...


1

I'll assume you have tried the following: reducing the power of the flash moving the flash further from the subject placing a diffuser between the flash and the subject to absorb a bit of light These will all reduce the amount of illumination arriving on your subject but may not be ideal for your situation. This is an atypical situation -- most ...


3

Here are some options: Find some shade If there's too much light for your style you need a location with less light :-) in mid-day sunlight you may need something pretty big to block enough light but still it's an easy option Shoot at a better time of day At early morning and late evening there's less light and you'll be able to get the aperture/shutter ...


0

You don't mention what kind of flash you are using. If You are using a Canon Speedlite, You should make sure it is set to ETTL otherwise, If you are using a manual flash You need to turn the flash power down.


11

Your camera is limiting your shutter speed to the 60D's maximum sync speed. If you were to use a faster shutter speed, you'd have black bars at the top and/or bottom of the frame, because the shutter curtains would be covering part of the sensor when the flash burst goes off. The only way to use a faster shutter speed than 1/250s with flash it to use ...


1

This is most easily achieved by using the change of density between air and water and a domed enclosure. When light passes from water to air through a piece of glass or plastic, it is bent by the transition. This effect can be used to form a lens that only applies when submerged. When above water, the air-air interface allows light to pass through ...


3

You can make lenses that are designed for a glass air interface too. Most famous of these is probably that of the Nikonos: Many Nikonos lenses, the "UW" series, were specifically designed for underwater photography only. It is said that, even to this day, no underwater lens matches the Nikonos "UW" lenses for sharpness and color saturation underwater. A ...


-4

The Camera Lenses does not know focus, it is just gears you can turn. Therefore air has nothing to do with focus. The camera uses a complex algorithm to determine when a picture is in focus or oof. And it will turn the gears via internal focus motor, or in lens motor to adjust focus. I think this may answer you question how camera determine focus: ...


-1

I think fixed aperture in zoom lens is nice when I shoot pictures of a blank wall. As I zoom in zoom out, the light on the blank wall does not change so there's no need to change aperture.



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