## Lens – How do I identify the original manufacturer of Soligor lenses?

First number = manufacturer
Third number = year

1 = Tokina
2 = sun
3 = sun
4 = sun
5 = ??? (maybe Samyang)
6 = Komine
7 = sun
8 = ???
9 = Cinema
31 = ??? *
A = Komura #
H4 = kavanone? #
H5 = Komine #
H6 = Komine #
H7 = Tokina #
H37 = Kawanon? #
M = ??? #
N = ??? #
R = #
T = Tamron #

* Six-digit lens date code unknown.
# The code for the date code of the letter is unknown.

"H" prefix tags: Lentar / Focal / Soligor / Sun / Vemar

Soligor lenses were also branded and sold: Reflex, Super Carenar, Prinzflex, Weltblick, Mirage, Infotar, Hanimar, Flexar, Elicar, Derek Gardenar, Porst and possibly Bushnell (Bausch & Lomb), J.C. Penny, Pallas, Berroflex and Aetna.

## Lens – What is the difference between the Canon 55-250 IS II and 55-250 IS STM lenses?

First, let's get rid of some nomenclature:

EF-S means a lens in the Canon EOS system that works only with cameras with APS-C or smaller sensors (if ever smaller sensors than APS-C EOS sensors are created). They can not be used with cameras with larger "full frame" 35mm film size sensors.

55-250 mm is the focal length of the lens. For an APS-C camera, a 55-250mm lens gives the same approximate field of view / angle that an 88-400mm lens would produce for a 35mm film camera or an FF digital camera. This is only important if you are familiar with 35mm focal lengths and want to know what the "equivalent" angle looks like with cameras of a different format size.

f / 4-5,6 refers to the maximum aperture of the lens. A lower aperture is a wider aperture that allows more light to enter the lens. In this way, a shorter shutter speed or a lower ISO value can be used if necessary. Both lenses have a maximum aperture of f / 4 at 55 mm. The maximum aperture narrows gradually at focal lengths between 55 m and 250 mm. At 250 mm, the maximum aperture is f / 5.6.

IS Image stabilization is a technology that counteracts the movement of the camera / lens during the exposure time. It allows slower shutter speeds without camera shake caused by camera movement when the camera is held in the hand than would otherwise be possible. It does not help with motion blur caused by the movement of the subjects in your photos. That can only be a shorter shutter speed.

II The Roman number two. This indicates that this is a second, updated version of a previous lens with the same name (except the suffix "II"). A subsequent version would be called "III".

STM Stepper Motor Refers to the type of autofocus motor used to move the focusing elements of the lens.

There are some important differences between the EF-S 55-250mm F / 4-5.6 IS II and the EF-S 55-250mm 1: 4-5.6 IS STM:

• Two different optical formulas. Although the names are very similar, the optical formulas of the lenses are not the same. The EF-S 55-250 mm 1: 4-5.6 IS II (2011) is Optically identical to the previous EF-S 55-250 mm 1: 4-5.6 IS (2007). While this is not always the case when comparing an original version with the "II" version of a Canon lens, the differences between the "55-250 mm" and the "IS II" of 55-250 mm are purely cosmetic, except an updated IS (image stabilization)) firmware. These lenses had 12 lens elements in 10 groups. The "STM" on the other hand has 15 lenses in 12 groups.
• The way in which the focusing elements are moved in the lens. The original "IS" and "IS II" (55-250 mm) had a micromotor autofocus. This is the most basic (and cheapest) AF motor type on Canon EOS lenses. They are good enough, but they are neither as fast nor as quiet as Ultrasonic Motor (USM) AF units in higher-class Canon EOS lenses. The newer "IS STM" uses a newer stepper motor to move the focusing elements of the lenses.

Optical formula

Of course, differences in optical design can affect the optical performance of the lens. In this case, "IS II" and "IS STM" are very similar from 55 mm to about 100 mm. Beyond 100mm, the general consensus of most reviewers is that the newer STM lens will maintain more or less the same "sharpness" at 250mm, while the older "IS II" will soften at 135mm and more greatest performance drop at the longest focal length of 250 mm ("zoomed all the way up"), especially at the edges and in the corners of the frame.

The other major difference in the optical design is that the increased number of lens elements in the "STM" is on the back of the lens so that the lens can use the internal focus. This allows the "STM" lens to focus without rotating the front of the lens barrel forwards / backwards when the focus is adjusted. The front barrel of the "IS II" turns and moves gradually as the focus is adjusted. The front cylinder of the "STM" moves inward / outward when zooming, but the cylinder does not rotate during zooming. Using polarizers or graduated neutral density filters that are affected by lens rotation can be a distinct advantage, as the filter does not have to be readjusted each time the focus distance is changed.

focusing

The STM autofocus motors are designed to be quieter and quieter than the micromotor AF. The benefits of capturing video should be obvious: the focus can be changed from one distance to another during a smooth transition, while being quieter and less likely to be picked up by the camera's microphone. Compared to micromotor lenses, the STM lenses tend to focus faster and to be quieter and quieter. The higher resolution USM lenses are optimized for still image capture. They are usually quite quiet, but they focus on focusing as fast as possible without worrying about "jerking" between the focus positions. The focus is on getting to the desired focus position as quickly as possible so that the still image can be taken NOW.

Another major difference between most micromotor AF lenses and STM is manual focus. To manually focus a micromotor lens, set the AF / MF switch from AF (auto focus) to MF (manual focus). The lens is then focused using a mechanical connection between the focusing ring on the lens and the lens elements within the lens. When you move the focus ring with the switch to & # 39; AF & # 39; move, the focusing mechanism may be damaged. When the & # 39; AF / MF & # 39; switch is on & # 39; MF & # 39 ;, the lens can be focused even if it is not connected to a camera.

STM lenses are all focused. There is no direct mechanical connection between the focusing ring and the focusing elements of the lens. When the focus ring is rotated, it sends a signal to the camera, which sends a signal back to the lens and instructs the focus element to move. The finest focus setting that can be made with manual focusing is a single step of the AF motor. This allows you to manually focus on full time, even if the "AF / MF" switch is set to "AF". In addition, the lens must be attached to a powered-on camera to move the focusing mechanism.

(Most USM lenses have a manual manual focus via a mechanical link between the focus ring and the USM ring inside the lens, allowing the lens to be manually focused even when not attached to a camera. By-Wire USM Lenses By December 2017, all but one have been discontinued.)

So what is "better"?

It all depends on what you want to do with the lens.

• The "STM" is a slightly better optical performance.
• The "STM" has a faster, quieter autofocus, but requires the focus-by-wire connection to focus in discrete steps.
• The "IS II" can be manually focused without any camera power and can be set finer than the smallest step of stepper motors in STM lenses.
• The "IS II" is usually cheaper, so that the money saved for another lens or other lighting device or other accessories can be spent.

For most people, the newer EF-S 55-250mm 1: 4-5.6 IS STM would be the more desirable option in all aspects except the budget. However, the older "IS II" is well able to take good photos that are almost the same as the newer model.

## Lens – What is the difference between the different image-stabilized Canon 18-55mm lenses?

The two most important options you will find at Canon are that they use the newer "STM" (stepper motor) design or the non-STM version "II" (which is used) a 18-55mm f / 3 , 5-5.6 can get micromotors).

The STM engines are much quieter … but they are also faster to focus. Even if you are not interested in the "sleep" feature (great for videos if you use the internal microphone) … being "faster" is generally always welcome.

One feature that really comes to my mind … is that the STM version now has "internal focus". In the older non-STM design (version "II"), the lens rotates the front of the lens when focused. If there is a polarizing filter on the lens, the filter rotates … and you will have to adjust the filter tuning again after each focus. In the "STM" version, elements are only moved internally. The front element does not turn anymore. This means that you do not have to constantly adjust the filter angle.

Other than that … Both lenses take 4 steps of image stabilization.
Both lenses have a decent look … with some optical errors (chromatic aberration).
The STM version has 7 aperture blades compared to 6 in the older version "II".

For those with deeper pockets … the EF-S 17-55mm 1: 2.8 IS USM. Its main advantage is that it provides the lower ratio of f / 2.8 at all focal lengths in its range. At the 55mm end, the two full stops are "faster" than the f / 3.5-5.6 lenses.

## Can you turn a 60mm macro lens into a 100mm macro lens?

I have a Canon EF-S 60mm macro lens.

Can I add an extension tube or teleconverter to emulate a 100mm macro?

If not, is there a solution?

## Lens Design – What makes the Canon RF 70-200 f / 2.8 much smaller than the EF version?

It is possible to image with a modest single element lens. We are sorry to report that the resulting pictures are second-rate. This is because all the lenses have aberrations that deteriorate. Opticians mitigate aberrations by combining numerous lenses. Some are positive (convex) and others negative (concave) in terms of performance. In addition, some are cemented together; others are at air distances. It takes all this to mitigate deviations. However, residual errors always remain.

If the camera were equipped with a lens with a single element and focused on a distant perspective, we could take a measurement from the lens center to the image plane. This value is the focal length. In a complex lens array, finding the point for this measurement is less clear. The point we need to find is called the back node.

Opticians can and must move the position of the posterior node. Now a long lens is a long focal length. The longer the focal length, the larger the magnification. A long lens is very desirable if you are interested in sports, wildlife or the like. However, it may be that a long lens is a bit awkward.

Opticians have a trick on their sleeve that physically shortens the lens barrel. This is achieved by moving the rear node forward. If the optician so desires, a complex array of lens elements may be constructed so that the posterior node falls into the air in front of the anterior element.

Remember that the focal length is a measure measured from the back to the image plane. The advantage of such a design is a shorter, less cumbersome run length. Let me add: A real tele-design differs from the long lens in that the telephoto lens is shortened in terms of the run length.

You should also be aware that short wide-angle lenses often position the rear lens group too close to the image plane. If so, there is no room for the SLR mirror mechanism. The optician, who wants more space for the back focus removal, will move the rear knot backwards.

## Selection of a lens for great depth of focus and short focal length

I designed my own night vision system with a DVD player screen + electronics, a 11.1 VDC lipo battery, two action camera mounting systems, a 2-7×32 riflescope, a PVC coupler (for eye relief), one CCTV camera and a lens a streamlight IR LED spotlight.

The lens is a Pentax Cosmicar C31631PL C1614ER C Mount 16mm CCTV Lens. The camera is a samsung scc-b2391 day and night digital camera.

Here is my problem. The setup works, I can display a picture successfully as planned, but I can not focus the picture clearly on the net and the target. I too have a bit of a fisheye effect. I suspect that a fixed focus and a mismatch in the format (camera 1/3 super HAD CCD lens 2/3 is) or are each to blame. Another point I may be able to contribute is my inexperience in setting up the Auto Iris, which was also a struggle for me. It works constantly now, without flickering or completely closing with changing light. My earlier setup was able to get a sharp, sharp image of both the crosshairs and the target. The problem was again that the image of the screen did not take up enough. The 16mm CCTV lens provides a nice full screen, but not sharp enough. How can I focus the crosshairs and the target? I know that someone who knows how to set up photographic equipment can tell me what to do.

UPDATE: I have now switched to a Pelco F1.6 / 5-40mm C surveillance camera lens for surveillance cameras. This has solved 90% of my problems. I am sure that I still have room for improvement so we would be happy to receive additional information.

## Surgery chart (Kirby) of the coherent sum of the lens spaces?

What does the Kirby / Surgery diagram look like for an associated sum of two lens spaces?

Question 1: is it just the unlink with $$p / q$$ Coefficients?
Question 2: If not, with which connection is the link to be solved? $$p_i / q_i$$ Coefficients?

## Lens – which non-MD lenses can be used with a Minolta XG-7 camera with adapter?

I've come across adapters that allow for the use of M42, T2, TX, and Adaptall mount lenses for Minolta cameras with SR / MC / MD mounts. You can customize some other mounts like DKL via M42.

The reason for so few adapters is not technical, but the market potential is limited. No new cameras will be produced with SR-based mounts. In addition, it usually makes more sense to adapt MD lenses to other systems than to adapt other lenses to MD.

• Most third-party lenses are available for MD mounting.
• Minolta lenses are very good. There are not much better system lenses that would be worth adjusting for much better prices.

Watch This YouTube Video: Comparison Of Cheap And Steep Glasses: \$ 50 Minolta Or \$ 950 Zeiss Loxia – The Difference Is Low.

## Lens – Canon EF 200mm 1: 2.8L II USM or Canon EF-S 18-200mm 1: 3.5-5.6 IS?

I need a recommendation. I would like to buy a telephoto lens and do not know much about photography. I look at these two options:

Canon EF 200mm f / 2.8L II USM:

• Fixed lens.
• Fast (f / 2.8).
• Effective 320mm on my APS-C (Rebel T6).
• No image stabilization.

Canon EF-S 18-200mm f / 3.5-5.6 IS:

• Zoombar (I'll probably use it at 80mm 80% of the time)
• Max 200mm effective.
• f / 5.6 at 200 mm.
• Image stabilization.

I would probably use it 80% of the time at 200mm to photograph animals (including birds) on large shutter speed shots (with enough light to use low ISO values ​​in most cases). Apart from that, I would probably do some portraits in good light, some sports photos in low light conditions and some animals in low light conditions (very unusual). What I want to know is, which is better for my case? Image stabilization or large aperture? I do not consider the fixed focal length to be an important disadvantage, but I'm not sure. What do you think?

I'd also like to say that the Canon EF 70-200mm f / 2.8L IS II USM or similar is probably the best solution for my needs, but it's too expensive. I think of something between \$ 600 and \$ 800. The same for Canon EF 70-200 mm 1: 4L is II USM.

## Canon EF 70-200 f2.8 III IS vs Canon RF 70-200mm 1: 2.8L IS USM lens

I have Canon 80D and plan to switch to DSLR or mirror regulators after a few years. Now I intend to buy Canon EF 70-200 f2.8 III IS. Is it worth it to invest in Canon EF lenses, as I can see the high trend and the popularity of mirrorless cameras. From the technical data, RF lenses with particularly convenient ring control elements are superior.

Please give your valuable advice on whether it is really worth investing in EF lenses now, and I would like to keep it for at least the next 10 years.

I shoot occasionally, not a heavy user.

Thank you.