nikon – How can I find a petal-style lens hood for my Nikkor 55-300mm f/4.5-5.6 (or any lens which doens’t have one)?

For a 55-300mm lens in general whether you use a circular or petal shaped hood won’t make that much of a difference in terms of performance. That is why few lenses in the telephoto focal length range use petal shaped hoods. For your lens in particular a petal shaped hood would be problematic since the front of the lens rotates during focusing.

The purpose of a hood is two-fold: To prevent off axis light that could potentially cause flare and loss of contrast from reaching the front surface of the lens and to provide a measure of protection from impacts to the front of the lens. Lenses with wide angles of view are more vulnerable to flare because of the “wider net” they cast in terms of how much of the total sphere around a camera is either within or just outside of the field of view of the lens. So a bright light source has a much better chance of affecting a wide angle lens than a narrow angle lens because it doesn’t need to be as close to the optical axis, in terms of angular degrees (º), to affect the image.

Hoods for zoom lenses are, at best, optimized for the widest end of the focal length range. For the hood to be optimized as you zoom in with a lens the hood would need to get progressively longer. Just using a longer hood would, of course, cause vignetting at the wider focal lengths.

Circular hood are simpler to design and produce and use less materials for a given angle of view. This tends to make them cheaper to produce. Circular hoods also tend to be a bit more durable than petal shaped hoods. They also work on lenses that rotate the front element during focusing and/or zooming.

For these reasons most telephoto zoom lenses use the simpler circular hoods. Even Canon’s fixed focal length “Super Telephoto” series use circular rather than tulip petal shaped lens hoods. Pretty much the only telephoto lenses that do use petal shaped hood are the 70-200mm f/2.8 variants from several manufacturers. For focal lengths very much longer than 70mm a circular hood would need to be much longer than is practical to use before the cutouts that give tulip shaped hoods their distinctive shape would be necessary.¹

This illustration demonstrates how a petal hood can be optimized for a particular field of view. In the case of the illustration the angle of view seems to be about 60º which would indicate a focal length of around 24mm. (A 24mm lens on a FF camera has a vertical AoV of around 53º and an horizontal AoV of about 74º.) Now imagine how long the pyramid of light entering a lens with an angle of view of only 15º vertical and 23º horizontal would be and it is easy to see why a hood optimized for such a lens would be several feet long!

enter image description here

If you are on a limited budget you might be able to find a pattern to make your own hood out of cardboard or similar material at lenshoods.co.uk. For use on cameras with cropped sensors try lenshoods.net instead.

¹ In fact, the cutouts on the hoods for (at least) Canon’s 70-200mm f/2.8 series of lenses are superfluous. One can tape thin cardboard around the rim of the hood, completely covering the cutouts, and still not experience vignetting at any focal length, aperture, and focus distance combination when using the lens on a full frame camera!

Canon Powershot Lens Error – Photography Stack Exchange

I have a Canon Powershot Camera SD1400 IS camera. It accidentally got dropped, and is now giving a Lens Error. 🙁

When I turn it on, it attempts to bring the lens out, but then retracts and says the following text:

Lens Error
Will shut down automatically
Restart Camera

In desperation, I looked at this question, and followed as many of the tips as possible. The only tip that gave any result was number 2, which says this:

Try pressing and holding the Menu, Function, Function Set, or OK while turning on the camera, or otherwise find a “factory reset” option.

On my camera, I pressed the func button and the on button, and then got this screen:

enter image description here

For those who wonder what it is, it’s just showing the time three minutes behind. When I press the left button on my camera, it changes the background color to the next color on the wheel. When I press right, it, again, changes the background color on the screen.

So what is going on here? Where is the factory reset button? Any help would be deeply appreciated, as this camera was a gift for me when I was 3. It wasn’t even me who dropped it.


Not a dupe. I explain why in the question body.

Also not a dupe. My camera lens, as explained, doesn’t stay outside. Instead, it tries to get out, but then retracts.

Equipment question – what in a lens name denotes when the filter mount moves during focusing?

“Internal focusing” is the term for that and it is rather common. Certainly a lot more so than “internal zooming” which makes a lens bulkier for transport and thus is comparatively rare for large zoom ranges. Off the cuff I remember the Panasonic DMC-FZ50 as a superzoom camera with both internal focusing and zooming.

To have either action “internal”, the position of the front lens group cannot significantly involved in the zooming or focusing action. Since macro lenses are focusing at very short distances (while having a much larger focusing range than a “normal” lens with additional closeup lens at the front would have), sacrificing space in front of a principal focusing group by adding a non-focusing group may be particularly unwanted, so they are a slightly more likely candidate for non-internal focusing.

filters – Calculating Lens Hood Dimensions

How can I calculate for a given lens, where in the periphery a theoretical lens hood would become visible?

This seems dependent on the size of the front element, focal length, and possibly other factors I don’t understand.

I build attachments for the front of my lenses to shoot through and selecting the appropriate lens has become challenge because I don’t understand this relationship. Thanks!

lens design – Are there lenses that exhibit absolutely no focus breathing?

If you are looking for a macro lens that does not noticeably breathe, the best one that I know of is the $1800 Zeiss 100mm f/2 Makro-Planar. The Canon 100L and non-L are both quite bad for this, and the Nikkor is worse. Sony 90mm FE macro also has very bad focus breathing. I am not sure about the Tamron non-VC or the Sigma, Tokina, etc., lenses. The Zeiss 100/2 only provides 1:2 magnification so you will need tubes or diopters to get to 1:1.

The Zeiss 135mm f/2 is also very good and provides up to 1:4. It is shorter than the fully-extended 100/2, so perhaps with tubes you could get greater working distance out of it.

In terms of deducing it from specs: if you can find a lens diagram, more symmetrical lenses will be better.

In the following example, a Sigma 150mm macro, the first several elements have a great deal of optical power (a very short focal length). Everything after the last ED element in the front is negative. In the back there is some positive stuff and then a couple of negative elements. This is a highly asymmetrical design, so it probably breathes quite intensely.

Sigma #106 lens diagram

In contrast to the Sigma’s autofocus-optimized design is a bit of a relic: the Zeiss 100mm Makro-Planar. The design dates from the 1980s but is a truly stunning design with perhaps decades of performance on par with or higher than its peers still up its sleeve. Its design is classic and simple, so it is a good choice with which to identify design elements.

Zeiss lens diagram

From the front, we have a split doublet made of a low dispersion glass. This helps with the axial chromatic aberration, though in this lens model that aberration still needs some work. Both elements have strong curvature on their front side and weak curvature in the same direction on back side. From the equation for the optical power of a surface, φ=C(n-n’) where C or curvature is the inverse of radius of curvature (i.e., 1/R), n is the refractive index of the ambient medium, and n’ is the refractive index of the second medium. At the first surface the ambient is air, at the second it is the glass.

Since the front curvature is greater than the rear curvature, it provides more optical power and these are net positive elements. Likewise with the third. The fourth has a greater back or rear curvature, so it is negative. This particular shape helps to flatten the image plane as well, and the meniscus third element helps to correct spherical aberration and coma. The first two have little spherical and coma, but the greater bend on the third provides more correction.

Elements 5 and 6 are cemented to correct color and have a strong negative power. If you cut the lens off after that doublet it would have a very long negative focal length, perhaps -500mm or something. Then there is a thin biconvex lens which provides more positive power, another biconcave, and another biconvex to finally focus the light to the sensor.

In front of the stop we have two “medium positive” elements, a strong positive, and a very strong negative. Behind the stop we have a strong negative, a mild negative, and two “medium” positive elements. The stop sits close to the more negative rear member increasing the relative power of the front group. If you imagine a magnifying glass, you get greater and greater magnification (more power) as you move from being very close to one focal length away. At one focal length you get no image, and beyond that you will get an inverted one. We are within one focal length, so the power increases the further back you go.

As you focus this symmetrical design closer it will approach unity imaging, e.g., an object 10″ in front of it will be projected 10″ behind it at life size. There may be issues in terms of aberrations, or mechanical issues that caused Zeiss not to pursue 1:1 magnification with it.

How to reduce shake on a Nikon DIGITAL DSLR 650-1300mm {2600mm-3900mm with adapters} zoom lens when on a tripod?

Nikon DIGITAL DSLR 650 1300mm zoom lens.
I have one of these lenses. In honour of this I bought a Zomei tripod. Tripod is of good quality but even so, the slightest breath of wind the lens shakes, creating at high magnification, the obvious effect to the image. Am I supposed to live with this? Or is there a way around it? I have seen a weight, a sandbag really, that can be suspended on a hook provided on the bottom of the tripod’s vertical mounting tube, but my nearby, long established camera shop in Stafford had no idea what I was talking about and are currently on lockdown anyway.
Assistance would be great with this please

Is a Canon 18-200mm lens a good idea?

Currently I have a T7, and I don’t like the non-versatility of the kit 18-55mm lens, i.e. I need more focal range. Is a Canon 18-200mm lens a good option for a replacement. I’ve seen a lot of reviews mostly positive about it, but I still would like some advice, I understand telephoto lens’ tend to have mediocre sharpness. If not suggestions are greatly appreciated.

lens – Does it actually matter considering DxOMark’s Perceived MPix Score for lenses?

Does this make the lens better than an L Lens?

It all depends on what way you mean when you use the word “better”:

  • Sharper at common apertures and focal lengths? At the center of the frame or over the entire field of view?
  • Less chromatic aberration at a particular focal length and aperture?
  • Less light falloff at a particular focal length and aperture?
  • Wider maximum aperture? (hint: that’s the biggest difference in the two lenses’ DxO Mark overall score)
  • Value for price?
  • Ruggedness and ability to withstand harsh environmental conditions?
  • Light and compact for hiking or long shooting session?
  • Guaranteed compatibility with future Canon camera bodies?
  • Autofocus accuracy? Autofocus speed? Autofocus frame-to-frame consistency?

As is often the case with comparisons between two zoom lenses, one might perform better at certain focal lengths and apertures and the other will perform better at other focal lengths and apertures. One might perform better in terms of chromatic aberration, the other may do better with regard to light falloff in the corners. One might give better image quality when carefully focused manually (as all tests at DxO Mark are conducted), the other may give better AF performance when tracking moving subjects.

There’s no simple way to define which lens is “better” than another. On order to decide which lens is “better” for a particular use case, the requirements of that use case must be considered and applied to the performance of each lens.

In the case of the two lenses in question used for sports/action in daylight conditions the superior AF performance of the Canon 70-200mm f/4 IS is probably a larger consideration than the slightly better optical performance (as measured by DxO Mark) of the Tamron SP 70-200mm f/2.8 Di VC. The comparison of the same two lenses at The-Digital-Picture is a much more mixed bag, with the Canon sharper in the corners across the focal length range and even in the center at 200mm and f/4 than the Tamron. The Tamron has a reputation for less than stellar AF performance when use on moving subjects.

On the other hand, for portraits and concerts the larger f/2.8 aperture of the Tamron is probably the largest differentiator between the two. Especially when used with an APS-C camera that limits the low light performance of the smaller sensor.

P.S. – Someone please explain to me how that is a 13 P-MPix vs. 9 P-MPix score at DxO Mark based on their own measurements?
enter image description here

The same comparison (200mm @ f/4) at The-Digital-Picture.

Please keep in mind that most online testing sites test a single copy of a particular lens model. Copy-to-copy variation between one example of a specific lens model and another example of the same model can, and often does, vary as much or more than differences between comparing a single copy of lens X and a single copy of lens Y when both lenses have similar focal lengths, maximum apertures, and build quality.

Roger Cicala, founder and chief lens guru at lensrentals.com, rarely publishes test results of lenses unless he has tested and averaged the results from a minimum of ten samples of a particular lens. But Roger tends to only measure MTF, or “sharpness”, at various points in the lens’ field of view. He doesn’t measure other things such as geometric distortion, peripheral light falloff, out-of-focus rendering (bokeh), etc. He’s published more than a few blog entries regarding copy-to-copy variation between “identical” lenses.

Measuring Lens Variance
Fun with Field of Focus II: Copy-to-Copy Variation and Lens Testing
Things You Didn’t Want to Know About Zoom Lenses

Should Canon 5D mk II autofocus be accurate enough for a f/1.2 lens?

According to this Blog post by LensRentals.com owner Roger Cicala, the 5DIII has less than 1/2 the standard deviation of the 5DII with regards to Phase detection Auto Focus. But to get that additional benefit, one must also use Canon lenses introduced since about 2010. All of the testing was done using the center focus point.

In general, using the center focus point should yield faster, more accurate focus with faster lenses such as the 50mm f/1.2L and f/1.4. The 5DII can be an exception to this rule. When shooting in AI Servo AF, if C.Fn III-07 is enabled, there are six small AF Assist Points clustered within the spot metering circle that are active in addition to the Center Focus Point. The location of these six AF Assist Points are not indicated in the viewfinder! Yet the camera may be using one of them pointed at something that has higher contrast than what is located behind the square in the middle of the viewfinder when it decides the focus distance.

Here’s the Map for the 5DII’s focus system.

Tech_42

The entire series will tell you just about everything you’ve ever wanted to know about phase detection AF accuracy and consistency.

Autofocus Reality Part 1: Center-Point, Single-Shot Accuracy

Autofocus Reality Part II: One vs. Two, Old vs. New

Autofocus Reality Part 3a: Canon Lenses

Autofocus Reality Part 3b: Canon Cameras

Autofocus Reality Part 4: Nikon Full Frame

equipment damage – Is it safe to test a (possibly) salt-water damaged lens (Tokina 11-16mm) on a new camera body?

My experience with saltwater damage is from my family business in an electronics repair shop where we handled board-level repairs for major manufacturers (including Sony & Panasonic.) The consensus always was from us, the manufacturers, and independent insurers that once we confirm a device has had saltwater in it then it is immediately “beyond repair”.

There are a few reasons… as a repairer you simply cannot guarantee that the device will work once it’s had saltwater in it. The way salt affects corrosion means that if a device passes testing in the morning you does not guarantee that it still might in the afternoon. Repairers simply won’t take the risk when the device might be back in their hands the vey next day.

Typically though you can wash it off, the true saltwater damage is rarely visible to the naked eye. Circuits are very fine so any corrosion issues don’t need to be especially large (or even visible to the naked eye) to cause either a broken or short circuit may occur and there’s no way for a repairer to spot it.

When you look at the potential damage that might come from the failure-mode of the lens it is the kind of damage that could take out your replacement body. If you can afford the risk that you have a ticking time-bomb on your hands that means you may have to replace the body (again) and the lens the very next time you use them (or it may be fine for years) then by all means go for it, but personally I’d chalk it up to experience and replace it now.