fujifilm – Is there a problem with this camera without lens cap?

A lens cap or lid is hardly necessary. Minor scratches do not really affect your image quality (PetaPixel source).

What a lens cap does Protect the lens during transport so you can shoot immediately – no accidental fingerprints or smudges on the way. Apart from that, the lens seems to be recessed, making the accidental fingerprint a rare event. As far as dust, water marks, etc., this camera is designed for use in places. You buy it to use it where you do not want to take a DSLR.

It'll get wet, be in salt water, get dusty, and probably fall a few times. Cleaning the lens before shooting becomes second nature to this type of camera anyway, The fact that there is no lens cap is therefore not a real loss.

Would an area outside the focus plane be focused by adding an external lens?

I'm doing scientific high speed recordings. I have a camera mounted in a fixed location with a Micro Nikkor 105mm lens. A fixed subject is displayed below which is a small mirror that is oriented 45 degrees. This allows the camera to simultaneously view the subject from the side and from below. Unfortunately, I can not simultaneously focus on the side view and the bottom view because the optical path length is different for both views due to the mirror.

I have considered a few possible solutions to focus on both views at the same time, and I would like to ask one of them.

If I place a small, separate convex lens in the camera's view so that the light from the side view of the subject passes through the convex lens into the camera lens, the bottom view, however Not go through the separate convex lens. Could I then focus both views with the right lens and placement at the same time?

If it works, can anyone point out the math needed to estimate the correct focal length for the convex lens?

If you can imagine another solution that solves the problem, I would also be interested in hearing about it.

Many Thanks!

How do I know if a lens is breathing sharply?

Recently, I got a 90mm macro lens, installed and run a focus bracketing app on my camera. Unfortunately, it has been found that this lens has focus breathing, which means that the actual zoom level in each image is slightly off.

How can I tell if a lens is breathing sharply before purchasing? (This was a Sony FE 90mm, in case you are curious.)

Does the image quality of the lens affect the technique of focusing and recomposing?

At least depends on the depth of field.

For example, if you are using a full-frame camera with 1: 1.2 / 85 mm and a portrait of the head and shoulders (1.65 m), the depth of field is 12.3 mm in front of the focal plane and 12.5 mm behind the focal plane.

What is the probability that the camera will move so that the subject is no longer close enough to the focal plane? I would say quite high, although I do not have a full-frame camera or an 85mm 1: 1.2 lens.

Use the right tool for the job. Your camera probably has multiple auto focus points, though in some cases the middle point is the most accurate.

On the other hand, a portrait with 135mm 1: 2.8 head and shoulders on a Canon 1.6x Crop sensor body (distance: 4.26m) has a DoF of 48mm in front of the focal plane and a DoF of 49.2 mm behind the focal plane. I would say, in this case, the risk that the subject is no longer focused, lower.

Compatibility – Are Canon EW-83J and EW-83H mechanisms compatible for mounting lens hoods?

I have a Canon EF 24-105mm 1: 4L IS USM lens and its lens hood EW-83H. I also have a lens hood EW-83J for EF-S 17-55 mm 1: 2.8 IS USM. I do not have a full-screen camera. My camera is a crop sensor.

When I use the 24-105mm lens with a crop sensor camera, that's 38.4mm-168mm. The 17-55mm lens corresponds to 27.2mm-88mm.

I am thinking of using the 24-105mm lens with the other lens hood EW-83J, because the 24mm lens hood (EW-83H) has to be relatively small due to the wide angle and this is not the case is. & # 39; It does not offer as much protection as the EW-83J bonnet. Of course, using the lens with a full-frame camera requires the EW-83H hood, so I do not intend to throw it away.

I looked at the lens hood and the diameters (81mm inside, 84mm outside) are the same, and the number 83 in the model number (whatever that means – I could not find a 83mm dimension in the mounting mechanism) is the same also. The mechanism for mounting the lens hood seems to be identical. However, I fear that the EW-83J bezel could get stuck when trying to attach it to the L lens due to a difference in the mounting mechanism that I could not see.

My question is: Can I use the lens hood EW-83J for the 24-105 mm lens intended for the lens hood EW-83H (when using the lens with a crop sensor camera)? Is it a good idea to use the EW-83J hood on a crop sensor camera, or can it affect the picture quality?

Lens – What exactly are tilt-shift lenses and why are they so important?

See Wikipedia.

The "shift" part causes the verticals to stay parallel (on the canonical architectural photo). Of course, you can correct the perspective in Photoshop, but this either loses pixels or definition. If your building is half as narrow at the top, when you fix the perspective, either shrink the bottom area (pixel loss) or widen the top area (but if you zoom in twice, it will not be sharpened).

The "tilt" allows you to have a focal plane that is not parallel to the sensor plane. I do not think Photoshop has a magical function to really sharpen something that is blurry on the first photo.

Optics – How wide must the front element of a lens be in terms of focal length and aperture?

Lenses with very narrow viewing angles require frontal elements that approximate the size of the entrance pupil. A typical tele-prime lens has a front element that is less than 10% larger than the entrance pupil at the maximum aperture of the lens. This is because the light rays collected by the lens are nearly perpendicular to the imaging plane and the entrance pupil is not much larger than the diameter of the front element.

For larger viewing angles and smaller subject distances, however, the entrance pupil can be much larger than the front element:

A simple single element lens:

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A multi-element compound lens:

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If the front element of a wide-angle lens were only large enough to fully visualize the entrance pupil of subjects centered on the optical axis of the objective, the objective would greatly vignette the light coming from the portions outside the axis of the frame , Wide-angle lenses therefore tend to have much larger frontal elements than the size of the entrance pupil, such that a larger portion of the entrance pupil is visible from the more peripheral parts of the field of view.

If parts of the field of view of the lens are obscured by the full view of the entrance pupil, this can lead to dark corners and strangely blurry lights. Look at large aperture lenses with even one normal Field of view:

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Such a lens should have "cat's eye" bokeh:

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Even if no mechanical vignetting is caused by the lens barrel, the entrance pupil appears from wider angles rather than an elongated shape than a circle.

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Compare these examples, which are all for full-frame cameras:

  • Canon EF 300 mm 1: 4 has 77 mm filter thread. 300 mm / 4 is 75 mm
  • Canon EF 100 mm 1: 2 has 58 mm filter thread. 100 mm / 2 is 50 mm
  • Canon EF 85mm f / 1.8 has 58mm filter thread. 85/1.8 is 47 mm
  • Canon EF 50mm f / 1.4 has 58mm filter thread. 50 mm / 1.4 is 36 mm
  • Canon EF 35 mm 1: 2 has 67 mm filter thread. 35/2 is 17 mm
  • Canon EF 24mm f / 1.4 has 77mm filter thread. 24mm / 1.4 is 17mm

Your 24-240mm 1: 3.5-6.3 lens with an almost 72mm front panel is more likely to reduce vignetting at 24mm and 1: 3.5 than the required entrance pupil for 240mm and 1: 6.3.

What is the cause of the "zoomed" bokeh appearance of photos taken with a first-class lens?

This is just a reasonable guess that I have never seen tested or specially tested with lenses that have been heavily corrected for field curvature and astigmatism that are closely related.

Most lenses that are highly corrected for field curvature are used for macro works or for reproducing flat two-dimensional documents / graphics. "In such cases, the aesthetic properties of the background blur do not play a major role in lens design.

Lenses with uncorrected or undercorrected field curvature often also show sagittal astigmatism. The two things can be combined, especially when used with a moderately wide lens with a very large aperture, resulting in mechanical vignetting. This can lead to a "whirling" type of bokeh, often referred to as the "Petzval effect".

Most lenses that produce such "vortex bokeh" involve some form of mechanical vignetting.

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The widely opened opening on the left shows mechanical vignetting when the entire entrance pupil is not visible because the tube of the objective blocks part of it from an area still within the field of view of the objective. Even without significant field curvature or astigmatism, such a lens exhibits "cat's eye" bokeh.

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Add an uncorrected field curvature and a scene with lots of bright, blurry lights to the equation. For example, a bright sky behind foliage, and you get the "vortex bokeh" effect.

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What is this vortex-bokeh technique and how can I achieve that?
What is the cause of this uneven bokeh effect?

On the other hand, if the lens is greatly corrected for field curvature to give it a more or less flat focus field┬╣ and the lens also has tangential astigmatism, the shape of the bokeh will appear to be radially stretched from the center of the lens as in the example photograph shown in the question. By greatly correcting field curvature, the astigmatism may shift from sagittal (if FC is not corrected) to tangential. When the sagittal MTF is higher than the tangential MTF, the tangential lines are blurred than the sagittal lines and therefore propagate in the direction perpendicular to these tangential lines over a larger area.

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What most of us view as "good" bokeh in terms of the quality of the fuzzy highlights is the lens design, which does not or only insufficiently correct field curvature and / or spherical aberration. This means that such a lens is not the best candidate for other types of photography, such as: Landscape or architecture, if we want a good sharpness to the edge of the frame.

The classic example of this is the Canon EF 85 mm 1: 1.2 L II. What makes it so great is the uncorrected field curvature it shows. This makes it a totally unsuitable lens for flat reproductions or taking flat test charts, as the focus field at the edges and in the corner in front of the flat subject has a considerable distance when the center of the lens is perfectly focused on it. If you want to capture a perfect photo from a flat test chart, the floor will be absolutely clean with the $ 350 EF 85mm 1: 1.8 with the $ 2,000 EF 85mm 1: 1,2 L II. But if you want to have this fascinating bokeh on the edges of a portrait, there is nothing better than the 85 / 1.2!

┬╣ Note that most lenses have some field curvature. The focus field is not a perfectly flat plane, even with a theoretically perfectly manufactured lens. Lenses that are strongly corrected for field curvature, such as Many macro lenses, for example, still have a focus box that looks more like a Lasagne as a flat plane. They are not perfectly flat, they are only flatter than uncorrected or less corrected lenses. To learn more about the subtleties of the focus field, I recommend reading Roger Cicala's excellent series:
Fun with focus field part 1
Fun with Field of Focus II: copy-to-copy variation and lens test

Lens – What is the real physics behind optical apodization?

Canon seems to be planning to introduce a 50mm with apodization for a more natural bokeh [1]but it is not the first one in photography [2], Wikipedia article is just an introduction [2]and does not develop the physics behind it.

  1. What is behind quantitative physics (mathematics)?
  2. What physical size can we build on?
    quantify this aesthetic quality that manifests in the bokeh?
  3. How do we make
    technically achieve this with a piece of glass?

[1] https://www.canonrumors.com/patent-canon-ef-50mm-f-1-4-with-apodization-filter/

[2] https://en.wikipedia.org/wiki/Apodization