I primarily shoot wildlife and nature photos and use lenses ranging from a 13mm fisheye for extreme wide angle to a true 1000mm prime lens for distant shots, however I can tell you first hand that learning to use long tele lenses can be a very exasperating experience.

Generally 300mm is considered the longest lens that can be effectively used in a hand held mode and even then it depends upon your camera and lens holding technique and the lighting conditions. While most people can hold a normal lens steady with shutter speeds of 1/60 or greater a 200mm lens will requires shutter speeds of 1/125 or greater and a 300mm will require 1/250 or greater for consistant hand held shots.

When using longer lenses the manner that you hold the camera becomes rather critical as well. For best results the left hand should be under the lens with the fore arm in a vertical position. When using zoom and/or manual focus lenses the lens is zoomed and focused with the left hand. For additional support the elbow can be rested in firm contact with your belly. The top of the camera body should be held tight against your forehead and the camera body held with your right hand with your right elbow extending horizontal to your shoulder. If you practice that grip you will have firm support on all three axis. It is also critical that you get in the habit of slowly and gently depressing the shutter button. Remember that any vibration or sudden movements will be exagerated when using long lenses.

The next thing to consider is that that longer the lens the shorter the depth of field at any given distance, therefore focusing becomes very critical when using longer lenses.

As I stated earlier, I have a full range of lenses, but in my humble opinion the best lens for general birdwatching or nature photography will have a maximum focal lengt of 300mm.

Fortunate for me, I can interchange my Pentax 35mm film lenses with my digital cameras so I can get the best of both worlds. If I had to go in the field with a maximum of only two lenses without question my choice would be my 28 to 70mm zoom for wide angle, normal and short tele shots and the 70-300mm for short to long tele shots.

I am attaching some photos to show you what can be done with a zoom with a max focal length of 300mm.

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Hand held shot of deer at 250yards using a Pentax ME Super (35mm film SLR) with a Sigma 70-300 manual focus macro zoom lens.

Hand held shot of a bee on a flower at 5ft using the same camera & lens. Lens set at 70mm macro mode.

Here is a hand held shot of a toad stool using my Pentax *ist DL digital with the 70-300mm set at 70mm macro

Hand held shot of two Blue Jays at 75ft using the same lens set at 300mm on my Pentax *ist DL digital SLR

Pentax *ist DL using the same lens at 60ft through a window

Pentax *ist Dl with a SMC Pentax 100-300auto focus set at 300mm at 15ft through a window

Lenses longer than 300mm will require a tripod

It should also be noted that the Pentax *ist Dl is the first generation of Pentax digital SLR's and only has 6.3mp resolution. I am certainly looking forward to my new Pentax K20d which I am purchasing for my birthday in April. That will move me up to 14.2mp of resolution with the shake reduction system while still allowing me to continue using all of my lenses.

Very informative lazypup. Thanks!

I especially found the distance to be helpful.

lazypup, your information is very helpful, and the photos are great. The one of the toadstool looks like I could just pick it right up. While I really like my Panasonic ZS3 12X point and shoot, I am seriously considering getting a 300mm lense, or my husband mentioned a doubler. He is the camera buff in the family so I am not quite sure which would be better, a doubler (our max. lens is 200mm), or a 300mm. Do you have an opinion on these two choices?

Thank you. Jane

I began my interest in photography with a Pentax Spotmatic 35mm SLR back in 1968 and if someone were to offer me a dollar each for all the 1.5x, 2x & 3x tele convertors that I have thrown away over the years I could take my GF out to dinner tonight..LOL.

Over the years I have stayed with Pentax for two reasons. First off, I have shot over 250,000 frames with my original Spotmatic and it still performs well. In addition, while Pentax has always stayed on the cutting edge of technology, often being the first to introduce new technologies they have managed to design their cameras in such a way that we can use any Pentax lens ever made on the brand new DSLR's. In fact, both Nikon and Canon build adapters that will allow you to use the old Pentax screw mount lenses on their new cameras.

Generally telephoto lenses are used for taking pictures of distant scenes or objects outdoors, well beyond the maximum limits of a flash unit so we are obligated to shoot under the available light conditions. If we are taking a picture of a stationary object we can easily mount the camera & lens on a tripod and compensate for low light conditions by extending the shutter speed but, if you are taking nature shots of birds and animals shutter speed is critical because the subject is not going to remain motionless long enough to permit long shutter speeds.

You may have also noticed that as we extend focal length we loose effective aperture. By example, your normal lens may be f1.2- f2, but if you extend to 200mm the maximum aperture will be in the order of f3.5 and at 300mm it will be f4.5 - f5.6.

Every time we close the lens one f-stop we must cut shutter speed in half to get the same exposure. By Example, if you have an exposure of 1/125 @ f2 then stop the lens down to f3.5 you must drop the shutter speed to 1/60 to get the same exposure.

Let us assume for the moment that you are shooting a scenic shot in late afternoon with your normal lens and you get an exposure of f2 @ 1/125. That would be a very easy hand held shot but what if you changed to a 300mm lens that has a maximum aperture of f4.5 ? You are losing two f-stops of light so you must now change the shutter speed 2 f-stops so the exposure would now be 1/30 @ f4.5 which is well below the 1/250 minimum for a hand held shot with a 300mm lens.

Years ago the big 3 camera manufacturers (Nikon, Canon & Pentax) did not even offer a tele converter but due to pressure from 3rd party aftermarket sources they do now offer them, although they keep them very low key in their advertising for good reason.

The main problem with tele converters, and what none of the third party manufacturers openly state is the "light insertion loss". Typically a tele converter will introduce a minimum of 2 f-stops of light loss and some go as high as 4 stops.

Now it can be argued that with most DSLR's we can compensate for the light loss by increasing the ISO index. (every time we double the ISO we gain one f-stop), which is true, but keep in mind that for every increasing in ISO there is a loss in image resolution and a significant increase in grain (called noise on digitals).

Tele converters also introduce both Chromatic & spherical aberrations which is a color & edge distortion that becomes very problematic when printing enlargements.

While on the subject of aftermarket products there is another option needs to be mentioned, that being mirror lenses. While the big 3 camera manufactures do make some very good mirror lenses, there is a long list of aftermarket manufactures that build inexpensive 500mm & 1000mm mirror lenses. Be very careful here because most of the inexpensive mirror lenses have a fixed aperture which is typically f-8. While they will perform marginally well for shooting scenics from a tripod, due to the fact that most birds and animals are most active in early morning or late afternoon those lenses are almost useless for nature photography.

Thank you lazypup. While I understand a lot of what you have told us, I am going to print your message and have my husband go over it with me. He first seriously started taking pictures in the 70s with a Nikon SLR, but he really likes the digital SLRs since he can take as many photos as he wants, view them on the computer (with my help), select the best, save them to a CD, print them or have them printed at a very low price.

Jane

Thank you for the information I like the picture of the cardinal its great. My Nikon d5000 had 12mp and it great took a picture of a fly the other day. I should try and post it have not done that in a long time. I wonder I have some picture on flickr and if i post the link if everyone would be able to see the picturs hmm