Canon ef

Share:

For those of us closely following Canon"s lens line, the Canon EF-S 24mm f/2.8 STM Pancake Lens looks exactly like a very successful lens we have seen before.That lens is the first Canon pancake-designed lens compatible with EOS DSLR cameras, the Canon EF 40mm f/2.8 STM Lens.When first introduced, we were all amazed at the tiny kích thước and light weight of the EF 40mm STM lens và even more amazed when we saw the image quality andoverall performance it delivered for a price equally as small và light as its form size and weight.

Bạn đang đọc: Canon ef

*

The EF-S 24mm STM lens first hit the streets in mid-November 2014, and it appears lớn be an exact duplicate of the EF 40 STM in an APS-C-format-only mount with a wider focal length that providesa near-40mm-equivalent 38.4mm angle of view on these smaller sensor cameras.With 40 STM-similar mechanical và optical performance, the 24 STM would be an incredible value at the same price point as the 40 STM.That this lens, in the USA at least, has a price tag of only 75% of the 40 STM"s current/normal street price assures me that this lens is going to land in a very significant number of kits.

*


Angle |Side

Focal Length / Focal Length Range

As you have likely already figured out, this is a 24mm fixed focal length (prime) lens.To say that the 24mm focal length is popular could be considered an understatement as Canon"s lens lineup alone includes 4 prime 24mm lenses và 15 zoom lenses with the 24mm focal length included.That is 19 out of about 78 total current lenses or about 25% of Canon"s lenses containing the 24mm focal length.

With the "EF-S" qualification, we know that this lens provides an image circle large enough to cover only an APS-C sensor.APS-C format cameras compatible with EF-S lenses include the Rebel (***D & ****D) models, **D models (such as the 70D) and the 7D series.These cameras have a 1.6x FOVCF that provides an angle of view from a 24mm lens that is similar khổng lồ that of a 38.4mm lens on a full frame camera.This is what that angle of view looks like:

*

Shown in this picture is the US Coast Guard Taney docked in Inner Harbor, Baltimore.A đôi mươi second f/8 exposure at ISO 100 was used for this image.

A 38.4mm lens is modestly wider angle than the 50mm focal length that is most often considered the "normal" or "standard" focal length và only very slightly longer than the also-wildly-popular 35mm focal length.These focal lengths are not greatly dissimilar và their lists of uses have significant overlap, but there is a perspective difference when framing a subject similarly.Below is a full frame comparison I created for the EF 40mm STM Lens đánh giá that shows this difference.APS-C-equivalent focal length angle-of-views are included in parenthesis after the actually-used focal lengths with the 25mm example being the relevant example for this review.

*


35mm (APS-C: 22mm) |40mm (APS-C: 25mm) |50mm (APS-C: 31mm)

In this example, the sides of the frame are nearly identical for each shown focal length,but the large trees in the background change form size greatly in proportion khổng lồ the foreground due to the different focus distances required for the similar framing.The wider angle lens will emphasize what is closer to lớn the camera in relation lớn the background.The wider angle lens will also emphasize human subjects" closest parts - often noses - making them noticeably larger in relation lớn the rest of bodies if used at a close distance.A 24mm lens is not a good choice for head shots (unless a distorted perspective is what you are going for).

Step back and your subjects will be happier with their portraits.Portraits not framed tightly are going lớn be only one of a huge range of great uses for this lens.The 24mm focal length is one that you could leave mounted for general purpose needs.

*

Aperture

Adding to the 24 STM"s multipurpose capabilities is the relatively wide f/2.8 aperture.While not especially wide for a prime lens in this focal length, f/2.8 is as wide as zoom lenses get with the Sigma 18-35mm f/1.8 DC HSM Art Lensbeing the sole exception at review time.To get a wider aperture lens into a kit is a great reason for selecting a prime lens & f/2.8 is a full stop wider (letting in twice as much light) than a typical kit lens covering 24mm(the EF-S kit lenses are typically f/4 max at 24mm).

An f/2.8 aperture is usually what I consider to be the minimum for stopping motion indoors or for night sky photography.

Following is an example showing the depth of field at full stop aperture changes.

*


f/2.8 | f/4.0 | f/5.6 | f/8.0 | f/11.0

Having only a 24mm focal length available generally disqualifies a lens for bird photography, but the 24 STM performed stellarly in this case.To keep this nhận xét a reasonable length, I"ll cốt truyện the complete cardinal picture story here.Notable is that the f/2.8 aperture can create some background blur with a close subject and a distant background, but the amount of blur is not extreme.

*

Image Stabilization

This lens does not have it.Not surprising is that a lens this small và inexpensive does not include the image stabilization, but the relatively wide f/2.8 aperture allows this lens khổng lồ be handheld in low light levels even without IS.

*

Image Quality

Before an actual lens is in hand, determining expected image quality usually involves reviewing the theoretic MTF chart(s) provided by the manufacturer.Here is the MTF chart for the Canon EF-S 24mm f/2.8 STM Lens along with comparison charts from the focal length and max-aperture-sharingCanon EF 24mm f/2.8 IS USM Lensand Canon"s other current pancake lens, the EF 40mm f/2.8 STM Lens.

*


24 STM |24 IS |40 STM

The thick lines show contrast while the thin lines show resolution.The solid lines show sagittal (lines radiating from the center to the outer image circle) results while the dashed lines show meridional (lines perpendicular to lớn the sagittal lines) results.The black lines indicate a wide open aperture while the blue lines show results at f/8.The left side of the chart shows center-of-the-image-circle measurement & the right side shows peripheral measurement.The higher the lines, the better the lens is expected khổng lồ perform.

The 24 STM"s chart is cut short (the right side is missing) due lớn its APS-C-sized image circle, but the chart predicted that this lens was going khổng lồ compete very wellwith the other two well-regarded lenses compared here.With a wide mở cửa aperture, it appeared that the 24 STM was going lớn be nicely sharper than even the 40 STM with meridional performance in the corner perhaps being an exception.At f/8, it appears that the two lenses will perform nearly identical with meridional performance in the corner again being slightly worse for the 24 STM.

With a 24 STM in hand, shooting the enhanced ISO 12233 resolution test chart was the first order of business (right after the sản phẩm images were captured).What we learn from these results is that this lens is nicely sharp with a wide mở cửa f/2.8 aperture và the results at f/4 are very sharp.Stopping down to f/5.6 brings some minor sharpness improvements, primarily in the corners.Stopping down lớn narrower apertures makes little difference in sharpness until diffraction rears its ugly head.See the f/16 results to clearly see the diffraction"s effects on sharpness.

My next immediate next task was tocompare the EF-S 24 STM to lớn the EF 40 STM.The 40 phối the benchmark for inexpensive lens image unique and from these test results, we see that the 24 is right there with the 40 in this regard.What I see is that the 40 STM is slightly sharper in the APS-C corners at f/2.8, though that is not especially surprising since the 40 is delivering a full frame image circle.By f/4, the sharpness difference is erased và the 24 STM"s barrel distortion remains the primary differentiator.At f/4, these lenses are producing very impressive image unique – image quality that is approaching some very fine lenses.

Field use has primarily confirmed what the lab is showing us, but looking at the results from a longer subject distance, we see more improvement in corners when stopping down.The following images were captured in RAW format and processed in Canon DPP using the Standard Picture Style with sharpness set to lớn "1" (very low).The buildings run at an angle through the plane of sharp focus, so I included an image of the entire scene to help you see where that sharp plane should be.The point of focus is on the above-deck cabin portion of the ship.These crops were from high on the right side of the frame.

*


While improvement in corner sharpness can be seen at a one or two stop narrower aperture, the biggest difference seen is the reduction in vignetting.The 24 STM corners have approximately 2.5 stops of shading at f/2.8.This amount is not unusual for an APS-C-format lens used at its widest aperture.At f/4, the shading is significantly reduced lớn about .8 stops with a generally-negligible .4 stops showing f/5.6.

Also negligible is the amount of flare this lens shows.Even with the sun in the corner of the frame, only a tiny amount of flare can be seen at f/11 và f/16.

Xem thêm: Triệu Lệ Dĩnh Phim Và Chương Trình Truyền Hình, Những Bộ Phim Nổi Tiếng Nhất Của Triệu Lệ Dĩnh

More than negligible is the CA (Chromatic Aberration) this lens shows in the corners.With strongly contrasting subjects in the mid & corner areas of the frame, expect khổng lồ see a modest amount of CA.CA is a relatively easy lens defect khổng lồ correct in post processing (or in-camera with some models) and relatively little image degradation is caused by the correction process.

More destructive to lớn correct is distortion & as I revealed above, this lens has some barrel distortion.The amount is modest, but if you have straight lines paralleling your borders, those lines may not appear straight or parallel without correction.Frame slightly wider than necessary if you plan to lớn correct the distortion.

The 24 STM shows an average amount of coma in the frame corners.Coma is perhaps most easily seen in night sky photographs.Coma causes the stars closest to lớn the corners of the frame khổng lồ appear more lượt thích little comets with their tails stretching toward the corners.

This lens" bokeh (referring to lớn the quality of the out of focus blur in an image) is decent.The corners can become a little busy, but specular highlights appear nice.Having an odd number (vs. An even number – not as in an unusual number) blade count, the 24 STM"s 7-bladed aperture shows 14-pointed stars radiating from points of light.

From an image unique perspective, I can say that my expectations for this lens have been realized.

*

Focusing

The 40 f/2.8 STM Lens I keep referring to lớn was the first available Canon lens with an "STM" (stepping motor) AF implementation.The Canon EF-S 18-135mm f/3.5-5.6 IS STM Lens was simultaneously announced,but the 40 STM Lens was the first available on the street.With the 24 STM and the announced-at-the-same-time Canon EF 24-105mm f/3.5-5.6 IS STM Lens,there are now 7 STM lenses in Canon"s lineup.Canon has obviously found success in the STM technology.

The 24"s STM implementation is nearly identical to lớn the 40"s STM implementation:

The STM thiết kế is a focus-by-wire AF implementation.The focusing ring does not turn during AF và FTM (Full Time Manual) focusing is supported.In AF mode, manual focusing is supported only while the shutter release is half-pressed as long as the camera is enabled for electronic manual focusing lens via the camera"s menu when this option is present(this feature is enabled by default).The lens" switch must be in the "MF" position and the camera meter must be on/awake for manual focusing khổng lồ be available.As is typical for "focus-by-wire" designs, the meter does have lớn be active for MF lớn be functional.

The focusing ring size, lượt thích the rest of this lens, is tiny.However, being located at the outer-most position on the lens barrel, the MF ring remains quite usable.The MF ring is easy khổng lồ rotate and is nicely smooth.Expect some modest subject size change in the frame when pulling focus using this lens.

The 24 STM"s front filter threads do not rotate with focusing.This lens uses a front-focusing design and the lens" inner barrel extends modestly at minimum focus distance (you can see this in the product images below).

*

There are no focus distance or DOF markings provided on this lens.There is no room for a distance window, & since the focusing ring is not directly connected khổng lồ the focusing gears (same as with most USM AF implementations), printed markings are not an option.Most AF lenses produced today have no significant DOF markings and I doubt that many using this lens will care about either of these missing features.

The Canon EF 40mm f/2.8 STM Lens was introduced with the Canon EOS Rebel T4i / 650D DSLR andthe T4i press release mentioned that "When used with Canon’s new EF and EF-S STM lenses, the camera can provide smooth và quiet continuous AF while recording video."AF performance during video clip recording continues lớn grow in importance, especially with Dual px CMOS AF recently introduced and especially with Dual px CMOS AF being included in theCanon EOS 7D Mark II announced alongside the EF-S 24mm f/2.8 STM Lens.The "smooth" portion of Canon"s claim has held true over all of the released-to-date STM lenses, và the "quiet" claim has also been true with the exception of the 40 STM.

The 40 STM is not a silent focusing lens.While it is not as noisy as the Canon EF 50mm f/1.8 II Lens for example, the 40 STM emits a buzz sound when focusing. The noise is not bad, but some buzzing motor noise is picked up by an in-camera microphone including that on the Rebel T4i/650D.In normal use, the 24 STM has the same noise cấp độ as the 40 STM.

However, on the newer Dual px AF DSLRs, the 24 and 40 STM lenses are much quieter than most non-STM lenses in Movie Servo AF mode (though some AF sound will still be picked up by the camera"s built-in mic).Notable is that the STM lenses are smoother in focus transitions than the non-STM lenses in Movie Servo AF mode & the micro-stepping drive closing/opening aperture is quiet.

While the 40 STM is not the fastest-focusing lens, it performs quite well in AI Servo mode & I expected the 24 STM lớn perform the same.I was nicely surprised lớn see the 24 STM focusing significantly faster than the 40 STM in side-by-side comparison.You will not call the 24 STM a fast-focusing lens when performing a full-extent focus adjustment, but in more-normal subject distance changes, this lens focuses with nice speed.

You can expect this lens lớn be able lớn track most in-motion subjects that the 24mm focal length is appropriate for in AI Servo AF mode.One shot AF is consistently accurate.

Excluding the 0.5x và 1.0x maximum magnification full macro/micro/makro lenses, there are 118 prime lenses in the site"s specifications database.Among these 118 lenses, the Canon EF-S 24mm f/2.8 STM Lens, at review time, ranks fifth for highest native maximum magnification (MM) with a 0.27x spec at the minimum 6.3" (160mm) focus distance.Here is a table showing some similar lenses.

ModelMFDMM
Canon EF-M 22mm f/2 STM Lens5.9"(150mm)0.21x
Canon EF 24mm f/1.4L II USM Lens9.8"(250mm)0.17x
Canon EF 24mm f/2.8 IS USM Lens7.9"(200mm)0.23x
Canon EF-S 24mm f/2.8 STM Lens6.3"(160mm)0.27x
Canon EF 28mm f/2.8 IS USM Lens9.1"(230mm)0.23x
Canon EF 35mm f/2 IS USM Lens9.4"(240mm)0.24x
Canon EF 40mm f/2.8 STM Lens11.8"(300mm)0.18x

Filling the frame with the cardinal subject I shared earlier in the review was not a challenge for this lens.Image chất lượng remains very good at this distance (and the feather detail is great).

If even 0.27x is not enough magnification for you, extension tubes will be your ally.With a 12mm extension tube mounted, the magnification range becomes 0.77-0.50x & with a 25mm extension tube mounted, the magnification range is between 1.38-1.11x.These numbers show that with-extension tube focusing can only be accomplished within a very short distance range, but the increase in magnification is very significant.This lens is not compatible with Canon Extenders.

*

Build unique & Features

This is a bare bones lens, but lượt thích the 40 STM, it feels well made.The non-weather-sealed toàn thân is constructed of engineering plastic with a standard metal mount.The other external components include a single switch, an extending inner lens barrel & a tiny MF ring.The MF ring has very little play/wobble in its design.

Bài viết liên quan