User talk:Dennis Bratland/RfC on shopping guides

RfC on shopping guides
What are examples of article content that meets the definition of a sales catalogue or price comparison service as described in WP:NOTCATALOG?

Explanation
The goal here is to see if there is broad consensus across many subject areas as to which specific examples of comparisons of products price, availability, features, performance, or sales are well outside the scope of what is encyclopedic, which are gray areas to be left to case-by-case editorial discretion, and which could be called good, the kind of content we would encourage.

Below are a number of diffs and quotes of content lettered A, B, C, etc. Please broadly categorize each example as:
 * Good Most or all of this content is encyclopedic. Should be encouraged, other articles should follow this example. An article this topic that lacked this type of content would be better if it were added.
 * Meh Should be left to case-by-case editorial discretion, or can't be determined based on this example alone.
 * NOT Most or all of this example is out of scope. Should be either deleted or significantly reduced and rewritten. The presence of of this content makes an article on this topic worse

Please ignore any solvable issues of completeness, appearance, formatting, typos, verifiability, neutrality, organization, cleanup, or tone. Focus primarily on the type of information and the context, e.g. a side-by-side comparison of data.

Feel free to add examples if you feel those given are insufficient.

Examples
Digital single-lens reflex camera#DSLRs compared with other digital cameras

DSLRs compared with other digital cameras
The reflex design scheme is the primary difference between a DSLR and other digital cameras. In the reflex design scheme, the image captured on the camera's sensor is also the image that is seen through the view finder. Light travels through a single lens and a mirror is used to reflect a portion of that light through the view finder – hence the name Single Lens Reflex. While there are variations among point-and-shoot cameras, the typical design exposes the sensor constantly to the light projected by the lens, allowing the camera's screen to be used as an electronic viewfinder. However, LCDs can be difficult to see in very bright sunlight.

Compared with some low cost cameras that provide an optical viewfinder that uses a small auxiliary lens, the DSLR design has the advantage of being parallax-free: it never provides an off-axis view. A disadvantage of the DSLR optical viewfinder system is that when it is used, it prevents using the LCD for viewing and composing the picture. Some people prefer to compose pictures on the display – for them this has become the de facto way to use a camera. Depending on the viewing position of the reflex mirror (down or up), the light from the scene can only reach either the viewfinder or the sensor. Therefore, many early DSLRs did not provide "live preview" (i.e., focusing, framing, and depth-of-field preview using the display), a facility that is always available on digicams. Today most DSLRs can alternate between live view and viewing through an optical viewfinder.

Optical view image and digitally created image
The larger, advanced digital cameras offer a non-optical electronic through-the-lens (TTL) view, via an eye-level electronic viewfinder (EVF) in addition to the rear LCD. The difference in view compared with a DSLR is that the EVF shows a digitally created image, whereas the viewfinder in a DSLR shows an actual optical image via the reflex viewing system. An EVF image has lag time (that is, it reacts with a delay to view changes) and has a lower resolution than an optical viewfinder but achieves parallax-free viewing using less bulk and mechanical complexity than a DSLR with its reflex viewing system. Optical viewfinders tend to be more comfortable and efficient, especially for action photography and in low-light conditions. Compared with digital cameras with LCD electronic viewfinders, there is no time lag in the image: it is always correct as it is being "updated" at the speed of light. This is important for action or sports photography, or any other situation where the subject or the camera is moving quickly. Furthermore, the "resolution" of the viewed image is much better than that provided by an LCD or an electronic viewfinder, which can be important if manual focusing is desired for precise focusing, as would be the case in macro photography and "micro-photography" (with a microscope). An optical viewfinder may also cause less eye-strain. However, electronic viewfinders may provide a brighter display in low light situations, as the picture can be electronically amplified.

Performance differences
DSLR cameras often have image sensors of much larger size and often higher quality, offering lower noise, which is useful in low light. Although mirrorless digital cameras with APS-C and full frame sensors exist, most full frame and medium format sized image sensors are still seen in DSLR designs.

For a long time, DSLRs offered faster and more responsive performance, with less shutter lag, faster autofocus systems, and higher frame rates. Around 2016-17, specific mirrorless camera models started offering competitive or superior specifications in these aspects. The downside of these cameras being that they do not have an optical viewfinder, making it difficult to focus on moving subjects or in situations where a fast burst mode would be beneficial. Other digital cameras were once significantly slower in image capture (time measured from pressing the shutter release to the writing of the digital image to the storage medium) than DSLR cameras, but this situation is changing with the introduction of faster capture memory cards and faster in-camera processing chips. Still, compact digital cameras are not suited for action, wildlife, sports and other photography requiring a high burst rate (frames per second).

Simple point-and-shoot cameras rely almost exclusively on their built-in automation and machine intelligence for capturing images under a variety of situations and offer no manual control over their functions, a trait which makes them unsuitable for use by professionals, enthusiasts and proficient consumers (aka "prosumers"). Bridge cameras provide some degree of manual control over the camera's shooting modes, and some even have hotshoes and the option to attach lens accessories such as filters and secondary converters. DSLRs typically provide the photographer with full control over all the important parameters of photography and have the option to attach additional accessories including hot shoe-mounted flash units, battery grips for additional power and hand positions, external light meters, and remote controls. DSLRs typically also have fully automatic shooting modes.

DSLRs have a larger focal length for the same field of view, which allows creative use of depth of field effects.However, small digital cameras can focus better on closer objects than typical DSLR lenses.

Sensor size
The sensors used in current DSLRs ("Full-frame" which is the same size as 35 mm film (135 film, image format 24×36 mm), APS-C sized, which is approximately 22×15 mm, and Four Thirds System) are typically much larger than the sensors found in other types of digital cameras. Entry-level compact cameras typically use sensors known as 1/2.5″, which is 3% the size of a full frame sensor. There are bridge cameras (also known as premium compact cameras or enthusiast point-and-shoot cameras) that offer sensors larger than 1/2.5″ but most still fall short of the larger sizes widely found on DSLR. Examples include the Sigma DP1, which uses a Foveon X3 sensor; the Leica X1; the Canon PowerShot G1 X, which uses a 1.5″ (18.7×14 mm) sensor that is slightly larger than the Four Thirds standard and is 30% of a full-frame sensor; the Nikon Coolpix A, which uses an APS-C sensor of the same size as those found in the company's DX-format DSLRs; and two models from Sony, the RX100 with a 1″-type (13.2×8.8 mm) sensor with about half the area of Four Thirds and the full-frame Sony RX1. These premium compacts are often comparable to entry-level DSLRs in price, with the smaller size and weight being a tradeoff for the smaller sensor.

Fixed or interchangeable lenses
Unlike DSLRs, most digital cameras lack the option to change the lens. Instead, most compact digital cameras are manufactured with a zoom lens that covers the most commonly used fields of view. Having fixed lenses, they are limited to the focal lengths they are manufactured with, except for what is available from attachments. Manufacturers have attempted (with increasing success) to overcome this disadvantage by offering extreme ranges of focal length on models known as superzooms, some of which offer far longer focal lengths than readily available DSLR lenses.

There are now available perspective-correcting (PC) lenses for DSLR cameras, providing some of the attributes of view cameras. Nikon introduced the first PC lens, fully manual, in 1961. Recently, however, some manufacturers have introduced advanced lenses that both shift and tilt and are operated with automatic aperture control.

However, since the introduction of the Micro Four Thirds system by Olympus and Panasonic in late 2008, mirrorless interchangeable lens cameras are now widely available so the option to change lenses is no longer unique to DSLRs. Cameras for the micro four thirds system are designed with the option of a replaceable lens and accept lenses that conform to this proprietary specification. Cameras for this system have the same sensor size as the Four Thirds System but do not have the mirror and pentaprism, so as to reduce the distance between the lens and sensor.

Panasonic released the first Micro Four Thirds camera, the Lumix DMC-G1. Several manufacturers have announced lenses for the new Micro Four Thirds mount, while older Four Thirds lenses can be mounted with an adapter (a mechanical spacer with front and rear electrical connectors and its own internal firmware). A similar mirror-less interchangeable lens camera, but with an APS-C-sized sensor, was announced in January 2010: the Samsung NX10. On 21 September 2011, Nikon announced with the Nikon 1 a series of high-speed MILCs. A handful of rangefinder cameras also support interchangeable lenses. Six digital rangefinders exist: the Epson R-D1 (APS-C-sized sensor), the Leica M8 (APS-H-sized sensor), both smaller than 35 mm film rangefinder cameras, and the Leica M9, M9-P, M Monochrom and M (all full-frame cameras, with the Monochrom shooting exclusively in black-and-white).

In common with other interchangeable lens designs, DSLRs must contend with potential contamination of the sensor by dust particles when the lens is changed (though recent dust reduction systems alleviate this). Digital cameras with fixed lenses are not usually subject to dust from outside the camera settling on the sensor.

DSLRs generally have greater cost, size, and weight. They also have louder operation, due to the SLR mirror mechanism. Sony's fixed mirror design manages to avoid this problem. However, that design has the disadvantage that some of the light received from the lens is diverted by the mirror and thus the image sensor receives about 30% less light compared with other DSLR designs.

Plug-in electric vehicle#Well-to-wheel GHG emissions in several countries]

A study published in the UK in April 2013 assessed the carbon footprint of plug-in electric vehicles in 20 countries. As a baseline the analysis established that manufacturing emissions account for 70 g CO2/km for an electric car and 40 g CO2/km for a petrol car. The study found that in countries with coal-intensive generation, PEVs are no different from conventional petrol-powered vehicles. Among these countries are China, Indonesia, Australia, South Africa and India. A pure electric car in India generates emissions comparable to a 20 mpgUS petrol car.
 * Example

The country ranking was led by Paraguay, where all electricity is produced from hydropower, and Iceland, where electricity production relies on renewable power, mainly hydro and geothermal power. Resulting carbon emissions from an electric car in both countries are 70 g CO2/km, which is equivalent to a 220 mpgUS petrol car, and correspond to manufacturing emissions. Next in the ranking are other countries with low carbon electricity generation, including Sweden (mostly hydro and nuclear power ), Brazil (mainly hydropower) and France (predominantly nuclear power). Countries ranking in the middle include Japan, Germany, the UK and the United States.

The following table shows the emissions intensity estimated in the study for those countries where electric vehicle are available, and the corresponding emissions equivalent in miles per US gallon of a petrol-powered car:

Plug-in electric vehicle#Cost of batteries and cost of ownership , plug-in electric vehicles are significantly more expensive as compared to conventional internal combustion engine vehicles and hybrid electric vehicles due to the additional cost of their lithium-ion battery pack. According to a 2010 study by the National Research Council, the cost of a lithium-ion battery pack was about US$1,700/kWh of usable energy, and considering that a PHEV-10 requires about 2.0 kWh and a PHEV-40 about 8 kWh, the manufacturer cost of the battery pack for a PHEV-10 is around US$3,000 and it goes up to US$14,000 for a PHEV-40. , and based on the three battery size options offered for the Tesla Model S, the New York Times estimated the cost of automotive battery packs between US$400 to US$500 per kilowatt-hour. A 2013 study by the American Council for an Energy-Efficient Economy reported that battery costs came down from US$1,300 per kWh in 2007 to US$500 per kWh in 2012. The U.S. Department of Energy has set cost targets for its sponsored battery research of US$300 per kWh in 2015 and US$125 per kWh by 2022. Cost reductions through advances in battery technology and higher production volumes will allow plug-in electric vehicles to be more competitive with conventional internal combustion engine vehicles.
 * Cost of batteries

According to a study published in February 2016 by Bloomberg New Energy Finance (BNEF), battery prices fell 65% since 2010, and 35% just in 2015, reaching US$350 per kWh. The study concludes that battery costs are on a trajectory to make electric vehicles without government subsidies as affordable as internal combustion engine cars in most countries by 2022. BNEF projects that by 2040, long-range electric cars will cost less than US$22,000 expressed in 2016 dollars. BNEF expects electric car battery costs to be well below US$120 per kWh by 2030, and to fall further thereafter as new chemistries become available.

A study published in 2011 by the Belfer Center, Harvard University, found that the gasoline costs savings of plug-in electric cars do not offset their higher purchase prices when comparing their lifetime net present value of purchase and operating costs for the U.S. market at 2010 prices, and assuming no government subidies. According to the study estimates, a PHEV-40 is US$5,377 more expensive than a conventional internal combustion engine, while a battery electric vehicles is US$4,819 more expensive. These findings assumed a battery cost of US$600 per kWh, which means that the Chevrolet Volt battery pack cost around US$10,000 and the Nissan Leaf pack costs US$14,400. The study also assumed a gasoline price of US$3.75 per gallon (as of mid June 2011), that vehicles are driven 12,000 mi per year, an average price of electricity of US$0.12 per kWh, that the plug-in hybrid is driven in all-electric mode 85% of the time, and that the owner of PEVs pay US$1,500 to install a Level II 220/240 volt charger at home.
 * Cost of ownership

The study also include hybrid electric vehicles in the comparison, and analyzed several scenarios to determine how the comparative net savings will change over the next 10 to 20 years, assuming that battery costs will decrease while gasoline prices increase, and also assuming higher fuel efficiency of conventional cars, among other scenarios. Under the future scenarios considered, the study found that BEVs will be significantly less expensive than conventional cars (US$1,155 to US$7,181 cheaper), while PHEVs, will be more expensive than BEVs in almost all comparison scenarios, and only less expensive than conventional cars in a scenario with very low battery costs and high gasoline prices. The reason for the different savings among PEVs is because BEVs are simpler to build and do not use liquid fuel, while PHEVs have more complicated powertrains and still have gasoline-powered engines. The following table summarizes the results of four of the seven scenarios analyzed by the study.

According to a study by the Electric Power Research Institute published in June 2013, the total cost of ownership of the 2013 Nissan Leaf SV is substantially lower than that of comparable conventional and hybrid vehicles. For comparison, the study constructed average hybrid and conventional vehicles and assumed an average US distance per trip distribution. The study took into account the manufacturer's suggested retail price, taxes, credits, destination charge, electric charging station, fuel cost, maintenance cost, and additional cost due to the use of a gasoline vehicle for trips beyond the range of the Leaf.

Comparison of digital SLRs

Key:
 * To save space, the "EOS" is left out from Canon model names.
 * ISO values include maximum sensor range, even if in manual mode ("H1", "Hi 1", etc.)
 * Continuous shooting: fps is "frames per second", indicates the highest speed for full resolution, without separate battery grip (i.e., not integrated into the body).
 * Memory card types: CF is CompactFlash, SD is Secure Digital.
 * Dimensions are rounded to the nearest whole number.
 * Weight: with standard battery unless noted otherwise.

Plug-in electric vehicle#Carbon footprint during production A report published in June 2011, prepared by Ricardo in collaboration with experts from the UK's Low Carbon Vehicle Partnership, found that hybrid electric cars, plug-in hybrids and all-electric cars generate more carbon emissions during their production than current conventional vehicles, but still have a lower overall carbon footprint over the full life cycle. The higher carbon footprint during production of electric drive vehicles is due mainly to the production of batteries. As an example, 43 percent of production emissions for a mid-size electric car are generated from the battery production, while for standard mid-sized gasolineinternal combustion engine vehicle, around 75% of the embedded carbon emissions during production comes from the steel used in the vehicle glider. The following table summarizes key results of this study for four powertrain technologies:
 * Ricardo

The Ricardo study also found that the lifecycle carbon emissions for mid-sized gasoline and diesel vehicles are almost identical, and that the greater fuel efficiency of the diesel engine is offset by higher production emissions.

Chart used on Battery electric vehicle, Electric car, and Tesla, Inc..



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 * Example user name (talk) 00:22, 19 February 2018 (UTC)
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