[malenisjaj]

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Because I'll get couple of lenses which I ordered, I have some questions.
I have a hood with standard 18-55mm DAL kit but, is it compatible with Pentax A and K (let's presume all lenses have the same diameter)? If not, where should I look to find them?

Kind regards!

[filoxophy]

Your current hood is a bayonet mount--you will need threaded hoods for your new (old) lenses.

Many A series lenses are 49mm diameter. Check the lens database here for the specs on your specific models.

---------- Post added 02-14-14 at 11:33 AM ----------

As to a source, I've been happy with the "metal vented" variety found on the bay. Just search for metal lens hood. Also have a few collapsible rubber ones, which are also nice--but one I bought has low quality plastic threads, so caveat emptor.

[Canada_Rockies]

If you are using a lens with a fixed focal length, buy a hood for a lens 1.5X the focal length to use when taking photos with a Pentax DSLR. It will better match the edges of the frame.

[malenisjaj]

I don't get that 1.5x? Does the hood needs to be one and the half times longer than focal length?

[stevebrot]

As noted above, your A and K series lenses were designed for hoods that attach via the filter threads. There are original equipment Pentax versions out there used (may be hard to find) or you can buy generic collapsible rubber or rigid metal versions on eBay and elsewhere. I have had good luck with rigid metal versions from heavystar on eBay (similar to the Kalt hoods sold at B&H). They are of decent quality, are modestly priced, and will accommodate a pinch type cap over the end.

Note that you can use a somewhat deeper hood with your APS-C dSLR than the lens would have used for 35mm film. For example, I routinely use a "normal" hood with my 28mm lenses.


Steve

[Na Horuk]

A hood is a hood, it does not care what series the lens is.
However! The DA 18-55mm uses a bayonet (as do many other modern Pentax lenses). Older lenses generally don't have that, they require a screw-on hood (screws into the filter threads).
The 18-55mm hood would also be a little too wide for most lenses, unless you are planning on putting it on a 18mm lens. What you want is a lens hood made for that focal length. But there is another twist - since you are going to mount that lens on a crop sensor DSLR, you can use an even tighter hood. Basically, take the focal length of the lens (for example 35mm), multiply it by 1.5 (= 52.5, so you can mount a hood made for full frame 50mm on your 35mm lens on crop sensor, because sensor is smaller). The hood must also be the correct size for the specific lensÄ' filter threads (52mm, 49mm are most common, but there are other filter thread sizes).
There are many ways to go about this. You can buy a genuine hood made specifically for that lens, but it will probably be expensive. You can go and buy a clone, a knock-off of the original. Costs much less, but these don't exist for all lenses. The final choice is third party generic lens hoods, where you just have to make sure it is not too tight (deep) and that it fits the filter threads of your lens.
You can search for hood by material (rubber, metal, plastic), or by shape (circular, square, petal/tulip/crown, vented).
Rubber is a flexible choice because they often allow you to fold them. They are also soft, so if you bump into something, it will take the brunt of force instead of your lens. Metal hoods are pretty hard, and they might be reflective. Generally not recommended. Plastic is often a good solution. Harder than rubber, but not as inflexible as metal.
Circular hoods are the most basic, sometimes they allow you to screw on a filter (they function as a step up ring).
Square hoods were part of Pentax' tradition, they look very retro, and they shape the image circle to fit the sensor better. But they are rather rare.
Petal hoods are very popular these days, they look "pro" and are easy to use. Some have a hatch, so you can manipulate polarizing filters.
Vented hoods are generally meant for rangefinder cameras (they have vents so they dont block rangefinder's viewfinder). Not the best solution for DSLR, but they look cool, very "Leica"

For A, M and K lenses, I suggest you first see if there are any genuine hoods available on the used market, otherwise get a regular petal hood. Often they are sold without a brand name, but you can search for "Mennon" hood. Circular rubber hood is also a popular choice, because they are often adjustable and foldable for transport

Edit: Also, I hear that you can buy a filter that has the hood bayonet. This might also be a good solution, so you can use modern bayonet hoods on older lenses. But be sure the bayonet will fit, as they are not all the same

[stevebrot]

I don't get that 1.5x? Does the hood needs to be one and the half times longer than focal length?

No. You want a hood that is deep enough to properly shade the lens while also not intruding into the field of view. For most lenses, the size that was appropriate for 35mm film is good enough for APS-C. At the wider end (say 35mm and shorter), however, you may wish to use a deeper hood than was originally intended for your lens. The reason being that most hoods designed for wide angle (35mm and shorter) lenses on 35mm film are too shallow to effectively shade the lens. With APS-C you have the advantage of being able to use a somewhat deeper hood.

BTW...don't bother with "tulip" hoods unless they were originally dedicated for your lens. As fpr the "vented" style hoods, they will work, but were intended for use on rangefinder cameras where the "vents" provide a means to not have the hood block the viewfinder. They will work on your camera, but are not worth paying extra for. They also do a poor job at blocking dust.

Regarding materials. I prefer rigid metal since they provide good protection for the lens. Almost all feature matte paint coupled with some form of flocking or light baffles on the inner surfaces to dampen reflection. The collapsible rubber kind tend to be somewhat shallow and offer little protection, but they are more compact in the bag. I would not buy a filter-mount plastic hood due to durability concerns.


Steve

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Last edited by stevebrot; 02-14-2014 at 10:00 AM.

[PPPPPP42]

I didn't read through all the stuff above so some of this may be repeated info.

The actual Pentax lens hood part numbers and thread diameters are listed with the lens descriptions here: Pentax K-Mount Lenses and Lens Accessories These would be the hoods that would have the correct coverage for a 35mm film camera.
Here is an interesting thread on decoding the part numbers: https://www.pentaxforums.com/forums/54-pentax-lens-articles/116760-genuine-pe...enclature.html

If a lens has a front element that rotates when you focus (the part with the threads that the hood or filters screw on to) then you need a round hood with no openings, square and tulip won't work because you would have to rotate it to the correct orientation after every focus adjustment.

Because I shoot film with the same lenses I go for the original hoods most of the time, though for you maybe collapsible rubber off ebay would be the best option.

A lens hood has 2 specifications, one is the thread diameter to screw the hood on (49mm for a Pentax A50 F1.4 for example) and the other is the lens focal length its rated for (50mm lens 300mm lens ect.) which tells you that the angle and depth of the hood isn't so much that it will stick into the picture.

[Canada_Rockies]

I guess I did not make my post clear enough. I meant that if you have a 50mm lens, you need to use a hood meant for a 75mm film lens to get the full hood protection from flare. I disagree mildly with the comment that this is effective only for wide angles, although wide angles are by their very nature more prone to picking up hot spots just outside the frame.

I can say that if I accidentally bump the built in hood on my M 400/5.6 so that it is not fully extended, and shoot near a light source I get more flare than when it is fully extended in the same condition. I've chimped and seen flare, reset the hood to its proper position, and gotten slightly less flare. Note the word slightly!

[malenisjaj]

Thank you all for detailed answers.

So, how do you combine filter (cpl) and hood in the old lenses?

[Na Horuk]

So, how do you combine filter (cpl) and hood in the old lenses?

If you want to use a CPL, you will need a circular hood. Square or petal can cause vignetting at some rotations. Your first option is to mount the filter on the lens and the hood on the filter, its a bit ridiculous, but whatchagonnado. Other option is a circular hood that has filter threads on the end, and you put the filter there. But these are slightly harder to find.

[rbefly]

Hello malenisjaj, Welcome to the Forum!
For using a CPL with the kit lens (52mm diameter filter thread), you would remove the hood, screw the filter on, roughly adjust for maximum polarization and re-mount the hood. With the hood in place it is difficult to turn the CPL outer ring to adjust the amount of polarization. Either use the pop-out panel, try to stick a couple of fingers between the 'petals' or take off the hood and try again.
Older lenses like K, M or A series have regular filter threads as on the DA, but no other provision for mounting a hood, like the bayonet on newer lenses. So, you would remove the hood, mount the CPL directly onto the lens and screw in the hood, to the outer ring of the CPL. Now, you merely turn the hood to adjust the CPL.
Everything moves together.
I'd suggest getting a few 3rd-party circular metal hoods in 49mm and 52mm, the typical Pentax sizes, if you're into using M/F lenses. There's three general shapes, wide, normal and telephoto.
Good luck!
Ron

[stevebrot]

I disagree mildly with the comment that this is effective only for wide angles

...Not really what I meant, but well-taken.

Most hoods originally made for, say 50mm and longer, will have adequate depth to shade that lens for both 35mm film and APS-C. Adding additional depth will not hurt anything, but I don't feel that it is worth agonizing over either. I sometimes use a longer hood on my fast 50s, but not always. At 28mm, however, the original hoods are very shallow and are not particularly effective even for 35mm film. On those, I usually use hoods originally intended for a 50mm "normal" lens when shooting on APS-C. I am not sure what would work best for 24mm or 20mm lenses on APS-C


Steve

[Lowell Goudge]

Do a search on the forums for a spreadsheet called hoodcalc. I uploaded it years ago.

It lets you determine the maximum length of a hood for a given focal length, hood diameter (not foil term thread but the actual hood diameter) and focal length.

[malenisjaj]

Hi again,
I found some genuine hoods for smc 135 f2.5 on ebay (they are expensive) but something is bothering me since I'm gonna buy cheap chinese copies. On this link there is original hood for 135mm f2.5 and 200mm f4 lenses. It's a hood for 58mm diameter lenses but then again, if you look in description, you'll see this: "Screw-in 55mm screw diameter."

So, will this hood (58mm) fit on smc 135 f2.5?