Panny 45-200 not a Zoom but Varifocal?

I've found that, nowadays, MANY a lens that claims to be a zoom is actually a varifocal. Since I don't shoot video, I don't really pay it much mind, but I can see that it would be an issue.

 

Very helpful post and when I had a copy of the 45-200 lens, it was also very sharp and contrasty

 

Hi
firstly, great shot!!

I think this is a semantic point, and most certainly the earlier zooms I had (and I bought my first zoom in 1976) were exactly that (vari focal). Eventually they modified designs to allow the focal point to remain fixed. But if you think about the word "vari-focal" it could also mean that the focal length varies.

I seem to recall that when "one touch" zooms came out that this became an issue ...

When it comes to picking the point and catching it I'd always use manual focus to confirm the focus on that spot and then grab. None the less your camera has done an outstanding job there!

PS: I notice a little vignetting on your image there (which works in that case) and its something I noted in my copy. I did a quick comparison with the new FD200f4 and found that it worked for me much better than the Pana45-200mm (which I've subsequentially sold). Not only did the FD give me f4 over f5.6 I found that the transmission of the lens was better resulting in another stop of shutter speed ...

http://cjeastwd.blogspot.com/2010/02/panasonic-45-200mm.html

PPS: I see (looking at your EXIF) that you were not at 200mm ... so the flexibility afforded by the zoom would be of course desirable. You must have been close to the action on your point on the track.

Stellar shot - well done

 

What you're thinking of is parfocal vs varifocal; zooms can function in either way.

 

That's what I didn't like when I used the Olympus 12-50.
When you change the focal length, the focus is totally lost for a short moment and then it refocuses.
I find zooming with such lenses quite annoying.

Anyway, I wouldn't trust a focus made before zooming even on my other lenses. I always refocus after zooming.
It's just the visual aspect (image blurred) that annoys me (it makes composition of the choice of focal length more difficult).

 

More than just a semantic point, it is a matter of proper terminology. It is true that all zooms are varifocals, but not all varifocals are zooms. The term "zoom" began life with the Zoomar lens created for TV work in its early days. It was quickly copied by other optical manufacturers. While variable focal length lenses have a long history, the Zoomar (a brand name BTW) maintained the same focus distance when the focal length changed. The distinction became that "true zooms" maintain focus while "vari-focals" don't. Prior to autofocus, this was an important distinction. When autofocus became ubiquitous, many lenses began to sacrifice "true zoom" characteristics in exchange for other optical advantages, relying on the AF to compensate.

BTW, one-touch designs were the first design used in zoom lenses on 35mm cameras. The two-touch designs were a later simplification, at first usually seen on cheaper lenses. Two-touch designs dominate today because of AF since you rarely need to manually focus.

 

I'm surprised that any autofocus lenses kept the focal point when their focal length changes ... interesting.

 

Indeed, few modern zoom lenses for still cameras are parfocal - most are varifocal. With the stills/video convergence it will be interesting to see if this trend reverses it self.

As to the term "zoom" clearly most stills photographers and manufacturers are perfectly happy calling a varifocal design "zoom" so I think trying to make a distinction of a "true zoom" is going to be fraught and obfuscating. Just call them parfocal and varifocal and remove all ambiguity when discussing the behavior of the focal plane when changing focal length.

 

Interesting post, thanks. I used to have the 45-200 and wish I had it back now. A lot of people dismiss it but I always liked it. Also props for the username, it's good to see MST3K fans still around.

 

As others have touched upon, prior to the wide adoption of autofocus, zoom lenses tended to be parfocal for ease of use.
These days, since autofocus is so common, many newer zooms are designed without a requirement that it be parfocal.

Note that the highly regarded $2300 Canon EF 70-200mm f/2.8L IS II USM Zoom is varifocal.

 

Hi

http://en.wikipedia.org/wiki/Semantics

and so proper terminology is indeed semantics. Semantics may or may not be of importance to a topic, but determining proper meaning is indeed an argument in semantics.

Can you explain that?

I think that like me (when I first replied) you are relying on experience to define that. I had a similar impression although a bit different. Some reading on the topic cleared that up for me (which I did after my post).

for instance http://en.wikipedia.org/wiki/Zoom_lens#History

well before TV....

[my bold]

I think problems come from the use of words, such as:

[italics from original quote]

in my view this use of "true" could be lept upon to disregard the others from being zoom lenses ... I'm not entirely sure thats a proper interpretation, but then that's where argument and interpretation would come in.

I think its also worth considering this: http://en.wikipedia.org/wiki/Parfocal_lens

which of course makes it clear that its not a simple matter of parafocal = zoom | varifocal != zoom

also not my understanding of history ... for instance a good many of the early FD zooms (see here) were two touch. For instance
http://www.canon.com/camera-museum/lens/fd/data/zoom/fd_85~300_45_ssc.html

was released in 1974 and not regarded as a cheap lens ...

http://www.canon.com/camera-museum/lens/fd/data/zoom/fd_24~35_35_ssc_as.html

released in 1978 and also not a cheap lens.

Of course I'm not sure if you mean earlier 35mm lenses than this...

that could be right ...

lastly, some history I found interesting

 

Hi

no wukkers ... its a corker of a shot and I've sent the link to a few biker friends  

given the speed if you were at 30 feet that's amazing capture work!!

take a bow

 

That is a great shot. I still use my 45-200 but always refocus when I zoom. I forgot the parafocal kind even existed.