Bothered abouts lens etc

Ok just managed to get my head around the field of view etc, so why do DSLR companys sell there len's at say 28mm to 200mm when in fact there not, when the field of view is increased just cant get my head around it why not sell it as a dslr lens with the correct information ,

i work in it so i am guessing its similar to the gigabyte senario if you by a 500gb drive you never have 500gb its about 465 gig

i have bought the lens below from forum member its in the link so will this be ok on my camera,as i understand this was designed for 35mm cameras

link

Because it is a 28-200mm lens, if they labeled it as anything else they'd be lying.

It doesn't matter if a lens is 'digital' or not, focal length is focal length. Just because the field of view is different on a DSLR compared to 35mm film SLR, does not change the focal length of the lens.

It's simply something you very quickly get used to.

And yes, that lens will be fine.

Dan

As we mentioned before, a 28-200mm lens on Pentax digital will hardly provide wide angle.

So you still haven't got the "all round" lens you wanted.

I would quite happily take out and shoot the twit who started all this "35mm equivalent" crap. A 35mm, or any Xmm, lens is a 35mm or Xmm lens no matter what.

When photography moved from glass plates to 120 film to 35mm film nobody had to worry about x.x factors; quite simply a 'standard' lens, meaning one that roughly equates to the field of view of the human eye, is on 6x6 120 80mm, on 6x45 120 75mm, on 135 55mm, on APSC digital 31mm or thereabouts. I cannot believe that Pentax and other manufacturers, who no longer make 35mm cameras, persist in equating everything they make to what is now a defunct format.

As the Canadian philosopher, Marshall Mcluhan, said 'We travel forward looking in the rear view mirror'

I quite happily expect Mac or Yves to correct my misquotation.

would i have been better going for a 18-200 then?
or will i be better off going for a wider lens and just live with the 2? i know defeats the object of the all in 1 but i know that i may of been a little to over hopeful in finding 1 to do all

Yes, an 18-200 would have been better for what you were originally asking for.

But now you're getting a 28-200, how about a 12-24mm as well? Would be an interesting combo.

thats what i think i will do or will see how i get on with the 28 mm and if its no good sell it and just go and buy the pentax 18-250 lens

AFAIK the Sigma DG lenses are made specifically for digital cameras. Won't these possibly give vignetting on a full-frame (i.e. film) camera?

Btw, is there such a thing as a good all round lens? I would rahter stick to my 18-55mm kit lens for general work, and use a dedicated tele or wide angle zoom if I need to reach longer or wider, respectively.

Yes. basically the lens that is supplied with the camera. In Ancient Times this was the 50mm lens, which was excellent quality and useable and abuseable for a large variety of subjects.

Then it became the 35-70mm zoom and later the 28-80mm zoom on film cameras. Now we have the equivalent of that - the 18-55mm.

It's cheap, it's surprisingly good and very versatile. It can be replaced by higher quality alternatives as we find the need.

ok so i have read this

Here's the front of the K10D without a lens. Like the K100D before it, the K10D works with any Pentax KAF2, KAF, or KA lens out there, and there are plenty to choose from. Due to the difference in size between the K10D's sensor and 35 mm film there is a 1.5X focal length conversion, so the 18 - 55 mm lens that comes in the lens kit bundle has a field-of-view of 27 - 82.5 mm.

is this because of the full senser senario so it still stays at 18-55 but on the smaller senser we cant take full advantage of it hence shorter on the wide end longer on the tele end think im getting it now,will i notice a massive difference between the 18 mm to the 29mm i have bought

Here play with this and decide for yourself link

On the end do you mean a 18mm on fullframe comapred to 18mm on APS-C, then yes you will sure notice a diference.

ok thanks for help Anvh

ok so if i bought a lens specifically made for dslr will i have true 18mm to say 200 or will it still be increased to whatever by the focal length its my understanding that it stays the same yes?as it was specificaly made for a dslr

I've no idea what you mean with your last post but the ones sizes are based on fullframe cameras so you need to crop it with every lens, make for digital or not.

The only thing that truly change is the angle of view everything else stays the same (focal lenght, dof, etc.) regardless of what kind of fullframe or digital camera you put it.
The APS-C sensor is smaller then normall 35mm film so that's why the angle of view changes.

We say that 18mm on digital becomes a 27mm on fullframe because the angle of views are the same for both and since that determents how big the subjust is relative to the film/sensor.
I hope you understand that, since it's quite hard to explain it.

Exactly my point. I regard my 18-55mm kit lens as an excellent all-round lens. My question was pointed at foxycce's signature.

The focal length of a lens stays the same whether it is mounted on a DSLR or on a film camera. Maybe it is easier to understand when viewed from the picture's side:

Aim your DSLR and a 35 mm film camera at the same scenery. If you have an 18 mm lens on the DSLR and a 27 mm lens on the film camera, the two images will cover the same area.