Does the lens's physical length increase when zooming? If so, from what to what?
1433436
The lens is about 3 inches long at 16 mm focal length and about 4 7/8 inches at 70 mm telephoto. It has internal focusing so it does not change length during focusing and does not rotate. I should add that this lens is superb, and the images are excellent and extremely sharp at all focal lengths.
1433437
I would say at max zoom it extends to about 6 inches. I don't have it to measure. Search on youtube for some demonstrations, that is what I did. Great lens!
1310573
This lens does not zoom. It has a fixed focal length of 25mm. It is an excellent lens, by the way.
1791107
Not sure what that means, but it does expand out and up to a full size tripod. You will love this lens! It is truely a walkaround lens, replacing my telephoto lens and my 18-55 starter lens.
2186187
The f stop (aperture) of the zoom lens changes as the zoomed focal length changes. On the P7700, which should be the same for the P7800, the f stop changes in the following seven steps as the focal length is zoomed from 28mm to 200mm: 28mm - 2.0 30mm 33mm 35mm - 2.2 38mm 42mm - 2.5 46mm 50mm - 2.8 58mm 66mm - 3.2 74mm 85mm 92mm 105mm - 3.5 117mm 135mm 152mm 175mm - 4.0 200mm
905102
It is and electronic zoom lens so when you push for a closer view the lens expands
1724619
The zoom works to the maximum (30x ?). Until you zoom in higher than 3 or 4 x you will get the circle showing from the lens adapter tube but this can be cropped later.
1381021
my setup is 7' high and 10' from the screen. The lens is in maximum zoom position to attain about 120" screensize.
628475
No, there is no means to fix the lens to a specific focal length. The total length of zoom ring travel is just shy of 90 degrees, end to end. The demarcation on the zoom ring, L to R as seen looking down at it as if it were attached to the body, is 24 - 20 - 18 - 16 - 15 - 14. The only hard control is the Manual/Auto autofocus switch.
2231433
The zoom locks only in the 18mm position. The lens is about 10 inches long when fully extended.
2250284
You must look at the thread size of your lens and not just what lens it is. These are two different things.
30437
the zoom rating may be because there is a small cmos sensor on this Camera, if it were a full frame sensor (as opposed to the small 'crop sensor' the lenses would have a true mm focal length, but because this, and most Digital SLR's under $2,000 use a 'crop sensor' so the camera body will automatically extend the focal length slightly from the lenses focal length.
2204554
Aperture is a ratio of the diameter of the opening to the focal length being used. On this and most zooms the diameter of the opening does not change when you change the focal length; hence the aperture slows. In the large, heavy zooms that are "2.8" throughout the zoom range, the diameter increases to maintain the light-gathering ability. And that costs money.
1449308
No you dont. The term 'focal length multiplier', and I am assuming you are referring to this number, does nothing to your focal length. It is a horrible term. It is your FOV (field of view) that changes.
1835811
No the reticle's size does not change with the zoom. Thus estimating distance with the mildot will change for different magnifications.
1420870
Isn't there a zoom ring on the top of the projector you can move left to right to increase & decrease the image size? I'd imagine it's next to the focus ring
2162155
The zooming mechanism is internal, responding to a zoom ring located just inboard of the manual focusing ring. The lens remains the same length no matter the value of the zoom.
111872
Yes, as are all lenses with a fixed focal length. (It doesn't zoom.) I love mine and use it all the time because of the very short focal distance.