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39

This is a Sigma name for one of their lens lines. It is not a general purpose term and really only has the marketing meaning Sigma ascribes to it. From the Sigma website, that definition is: Engineered for today’s photographer who wants to do it all, our Contemporary line combines superior optical performance and compactness for high-performance lenses ...


27

Because that rainbow is partially obscured by your subject, I would tend to believe that it has nothing to do with any of your equipment. Rather, there was something in the room acting as a prism and diffracting light into a rainbow pattern that just happened to fall within the frame of what you were shooting. It might be that the source of the light was ...


25

Your old D80 had a focus motor built into the body that connects to a mechanical coupling on Nikkor AF lenses to move the focus elements in the lens. Your D5300 does not have a focus motor in the body. To use autofocus your D5300 requires that you use Nikon AF-S or AF-I lenses or the equivalent third party lenses (such as Sigma's HSM or Tamron's USD and PZD ...


22

I think you are putting too much emphasis on the "digital" part of the lens' DG designation. It seems to be more to differentiate them from "digital" lenses that are APS-C only. Sigma calls their current APS-C only lenses "DC". When digital SLRs first began to gain a foothold in the market, they almost all had sensors that were APS-C or similar sized. So new ...


21

Yes you are looking at clipping by the mirror box, I'm afraid it's unavoidable when using a lens with large aperture and exit pupil close to the film plane at certain focusing distance. Even if the mirror box doesn't clip the light cone the lens barrel will (for off axis points of light) leading to cat eye bokeh. Here's an example from a full frame camera ...


18

Yes, lenses designed for digital sensors have several differences from their older film based camera lens counterparts. One of the primary differences is that digital sensors are more reflective than film, so anti-reflective coatings are applied to the rear element of a digital lens. This helps prevent reflections off the sensor that could result in image ...


15

Based on your comment, you have a Sigma 17-70mm f/2.8-4 DC Macro OS HSM Lens, which is an APS-C lens, on a full-frame camera. An APS-C sensor is smaller than a full-frame sensor, so the lenses that are designed for these cameras project a smaller image circle. APS-C specific lenses aren't designed to be used with with full-frame cameras. (See this post for a ...


15

It is a common problem when using some 3rd party lenses. Just turn off the in-camera lens corrections.


12

The lens is a varifocal lens. Basically, it's a lens that changes focus as the focal length changes and it's quite common. Parfocal lenses, ones that maintain focus on zoom change, exist but are typically more expensive as a result. Long story short, it's normal for a large number of consumer zoom lenses.


9

I think you've got a Minolta A-mount lens. Compare to this photo (image borrowed from here): Minolta and Konica merged at some point and were subsequently acquired by Sony, and this mount is apparently still used by Sony as the "Alpha mount system".


9

You are apparently using a Sigma DC lens on the full frame Canon EOS 6D. Sigma DC lenses are designed to be used on "crop body" cameras. That is, cameras with APS-C or smaller sensors. APS-C sensors are 24x16mm or smaller. SIgma DC lenses only need project an image circle large enough to cover an area 24x16mm with a diagonal measurement of just under 29mm. ...


8

The Sigma dock only works with select Sigma lenses. The lens needs to have the needed firmware to respond to the commands sent by the dock. Even Sigma lenses that are not part of their 'Global Vision' selection (ART, Sports, Contemporary) can not be calibrated using the Sigma USB dock. So how i.e. does Sony 100mm lens for E-mount is calibrated? Is is ...


7

Here's a little context for comparing the various versions of the Canon 70-200mm "L" lens series: EF 70-200mm f/2.8L was introduced in March 1995. This design is almost 25 years old! EF 70-200mm f/4L was introduced in September 1999. The design is almost 20 years old. EF 70-200mm f/2.8L IS was introduced in September 2001, over 17 years ago. EF 70-200mm f/...


7

You don't really need the dock until you need to install a firmware update, or until you decide you want to fine tune the lens. My suggestion: don't buy the dock until either of those situations arise. No need to spend the money now because you might want to do something later. You can also rent the docks from some of the lens rental places (lensrental.com ...


7

Is there a reason why Canon and Nikon allow third party makers to make lens that provide similar specs to first-party lens such are AF, IS and aperture control when they sell for less? Controlling a product line that has the support of many third parties is much more profitable than trying to build and sell every product yourself. Canon and Nikon don't just ...


7

This is probably because some cameras disable autofocus at slow apertures. The camera manufacturers think that performance won't be good enough, and so they disable it. The third-party lens is reporting inaccurate information to the camera so that it will work anyway — slow and sometimes incorrect, perhaps, but at least the camera will try. Exposure might ...


6

Lens performance is linear, the quality of the projected image at f/1.4 in good light is exactly the same as the quality of the projected image at f/1.4 in poor light. The sensor is what matters for low light performance. Secondly you can't really compare a 50mm to a 100mm lens, you get very different images. To answer your question, the Sigma is optically ...


6

I'm in the process of choosing a 35mm myself, and I think I'm leaning towards the Sigma (need to look into how the Bokeh looks on both the Sigma and Canon). If you look at Roger's take over at Lensrentals it's clear that they think the Sigma is the superior lens. The Digital Picture also seems to have a liking for the Sigma, so does dpreview.com, it seems ...


6

Comparing two very similar lenses like the Sigma 18-50mm f/2.8 EX DC Macro and the Tamron 17-50mm f2.8 SP XR Di II LD VC Lens in terms of sharpness can be difficult. Often one lens will perform better at a particular focal length and aperture, while the other will perform better at other focal length and aperture combinations. Even at the same focal length ...


6

There is one significant difference between film and digital sensor for lens optics - digital sensors have a bit of glass and some filters in front of them. The lensrental.com blog has a pretty extensive series of posts on the effect of the sensor stack (short version, there is a very real effect for large aperture lenses) - so it is quite possible that the ...


6

Some 'film' lenses designed for 35mm rangefinder cameras have a rear element which lies quite close to the plane of the film or sensor (mostly wide-angle lenses). These work fine for film, but when used on a digital camera cause quite noticeable colour shifts to the left and right of the frame. This is due to the extreme angle of the light from the rear ...


6

Neither of those lenses are really what most macro specialists would consider a macro lens. For a lens to be considered a true macro lens it should be able to project a life sized image of the subject onto the image sensor or film. If you're taking a picture of a 20mm long bug, a macro lens should be able to focus close enough to project an image of the bug ...


6

The first sample image in the question is focused well in front of the central pillar. The second is focused well behind the flowers. You have told us that you are using single point AF but you haven't told us which AF mode you are using: One Shot, AI Servo, or AI Focus? If you're trying to focus and recompose using AI Servo the camera will refocus when you ...


6

Nikon doesn't tell Sigma how their TTL protocol works (and Sigma does not pay to license it). The communication is reverse engineered. Sometimes, the protocol used varies slightly from camera body model to model — and sometimes, that variation means that the guesses Sigma made are out-of-spec and communication breaks. Sometimes, Sigma updates the firmware of ...


6

It sounds like your Sigma 24-70 has sticking aperture blades. If it happens only intermittently, you can try and free them up. Select a small aperture like f/22 and use your depth of field preview button to open and close the aperture blades rapidly. I have an old Canon 28-70mm f/3.5-4.5 from 1989 that used to do this. I didn’t really use this lens much, ...


6

However, if I understand correctly the aperture need to be multiplied as well, which results in an f2.1 and means I am losing at least an f-stop. In short: No. If you use a FF-lens with an APS-C sensor, part of the light that is collected by the lens is not hitting the sensor but the amount of light that hits a part of the sensor stays the same (as long as ...


5

I had this quandry a year or so ago and researched it to death, and also tried both the Canon and Sigma lenses to see how they compared. In my experience the Canon 10-22 far exceeded my expectations. It's a great lens - with near on L quality optics (just like the EF-S 17-55 f/2.8 is). The Sigma did not have the same build quality nor did it have the ...


5

If the lens is stuck to the camera, you most likely have a distorted barrel. Most often this happens if the lens bumped against something while being attached to the camera. This can deform the lens mount and sometimes also some parts inside the lens. This can prevent the zoom/focus ring from turning smoothly. I had that issue with some heavier lenses over ...


5

It depends. The Canon flashes you listed in your question use pulsed light from the Master unit to tell the Slave units when to fire and how much power to emit. This allows proprietary communication between the Master and Slave units and allows for use of Canon's E-TTL automatic exposure system as well as permits the photographer to set manual power levels ...


5

This photo is severely back focused. Areas about 15-20 feet behind the main subjects are in focus. Some things to keep in mind: When using wider apertures, especially combined with larger sensors, Depth of Field becomes shallower. So any focusing errors are more apparent. This is especially a problem in low light when most camera's auto focusing systems ...


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