I have also been a serious amateur / semi-pro photographer since the early 1960's and like you, when I retired I decided to take up Wildlife & Nature photography as my retirement hobby primarily to gie myself an excuse to get out of the house regularly, but even more specifically because I suffer from C.O.P.D. and I find taking long nature hikes carrying a 30lb backpack of photo equipment very theraputic, as an example, one year ago I couldn't walk to the mailbox without carrying a portable oxygen tank but today I think nothing of 5 or 10 mile hikes and I have not even had the O2 equipemtn for the last 6 months. According to my book, Birds of Ohio, there are 413 species of birds native to the state of Ohio. To date I have photo documented 119 species either in my yard or within walking distance of my house. Bird photography presents a number of unique challenges and with experience you will find that your technique is every bit as important as your equipment. Most birds fly between 20 and 30mph while some of the hawks and raptors are capable of speeds in excess of 70mph. This means that while in flight most birds are moving 30 to 45ft/sec which makes it nearly impossible to focus on birds while in flight, therefore if we have any aspriaton of getting flight action shots we have to anticipate where the bird will be, then set our equipment up in advance and await an opportunity to take the shot. Obviously shooting birds when they are still is much easier, but keep in mind that birds are very elusive so we must provide some means to attract the bird to our viewing area. IN winter this is very easy, we simply put up bird feeders, then sit back and wait for the birds to come to us, but what do we do in summer? Birds are opporunists and for basically the same reason that people frequent fast food restaraunts, birds can easily be attracted by bird feeders, bird baths, small decorative ponds in your landscaping and selected flowers and shrubs that attract birds. If your into capturing images of birds in their wild habitat you could do as I do, don full camoflage and stake out a spot where you have full view of wild fruits, berries, corn fields etc. Oh yes, I realize that this may seem gross to some, but don't overlook the photo opporunity of staking out a vantage point where you can watch some road kill. You will be amazed how many birds are scaavengers. Although much more difficult to get a good viewing angle, you can get some very unique photos ir you can find a nesting site, but be careful here. If you repeatedly get too close to a nesting site the parents may abandon the young. Under no circumstances should you ever touch a nest becuse that would leave your scent and the parents will nearly always leave. Now to answer your original question, what lenses do you need? Let me begin by clarifying a point for you. Rgardless of what kind of camera we use, a normal lens has a focal length equal to the diagonal measurement of the negative format or the electronidc sensor. By example, a 35mm film camera produces a negative that is 24x36mm therefore the diagonal measurement is 43.2mm. (due to the physical space reqquirements of the multiple elements, aperture and focusing linkages the industry has accepted 43 to 55mm as the normal lens). Any lens which has a focal length longer than the Normal lens is said to be a Telephoto lens. Generally lenses up to 3x the normal focal length are defined as telephotos while lenses longer than 3x the normal focal length are defined as super telephotos. Lenses with a focal length that is shorter than the normal focal length are called "Wide Angle" lenses. Lenses with a fixed focal length are defined as "Prime lenses" while lenses with a variable focal lenght are said to be a "Zoom Lens" meaning that is can be zoomed from its minimum to its maximum focal lenght, thus you could have a zoom wide angle or a zoom telephoto. On cameras that have a fixed lens they often define the focal ength by a number, by example, they may say the camera has a 10x zoom. In this case the numbrer is multiplying the focal length of the normal lens for that format, thus while the normal format for a 35mm film camera is 43mm, a 10x zoom would equal a 430mm lens. For 35mm film cameras or DSLR's a 300mm lens is considered the longest lens that can consistantly be hand held and they should only be used in hand held mode when the shutter speed is 1/125 or greater. Lenses longer than 300mm or in situations where the shutter speed will be less than 1/125 it will require a monopod, tripod or other suitable means of support. The actual diameter of the lens aperture can be mathematically computed by dividing the lens focal length by the index number, by example, if you have a 50mm lens set at f-2 the actual diameter of the aperture opening is 50/2= 25mm while a 300mm @ f-2 would have an aperture opening of 300/2= 150mm however due to the difference in angle of view both lenses would produce the same light level at the film plane. If we then examine the complete f-stop scale we would find that the the indexes are such that increasing the index one stop will reduce the cross sectional area of the aperture to 1/2 the cross sectional are of the previous aperture opening. If you then examine the shutter speed scale you will note that each increment is approximately double the time of the next higher shutter speed. Exposure is a combinastion of time and light intensity, thus if we change the f-stop one stop we either double or halve the amount of light striking the film or sensor, and if we change the shutter speed on index figure we also either double or halve the light to the film. In this manner we can change the overall exposure one f-stop by either changing the aperture setting or the shutter speed one index. You could use a 200mm lense with a doubler as was siggested before, but when we attach a doubler the actaul apertue size remains constant while we double focal length so we instantly loose one f-stop. In addition, we generally loose another f-stop to the light loss through the glass lens in the doubler. As a result the actual insertion loss of a doubler is typically 2 f-stops and some cheaper after market doublers have an insertion loss of 3 f-stops. When i first begani my interset in photography a built in light meter was still a new feature and in those days we had to learn how to eyeball an exposure. (When using my old manual focus pre-set lenses I still put my camera in manual mode and eyeball the exposure for practice) ISO is the actual shutter speed required to produce a proper exposure at f-16 in mean daylight at noon at the equator. As you move north of shuth of the equator the angle of incidence of sunlight changes and we must compensate the exposure, thue in the USA in bright sunlight at noon in mid summer the proper expose shutter speed would be equal to the ISO number with the lens set at f-16 and we loose one f-stop for each two hours before or after noon. Keep in mind that birds are most active in early morning or late afternoon. Using the aabove formula, if we are shooting a picture at 4pm on a bright summer day in mid summer our we could set the shutter speed to the ISO speed and set the lens to f 5.6. Keeping in mind that we want a shutter speed of at least 250 to stop action we must then use ISO 400 and if its a cloudy day or in shade the exposure would be f-4 but our lens will only open to f 5.6 so we must then increase the ISO to 800. If we were to attach a doubler we would need to push the ISO two more stops to 3200 and risk a lot of image loss to noise. In my humble opinion the best economical lens for what you want to do would be a 70-300mm f 4-5.6 I would also strongly encourage you to get a good heavy duty tripod and a remote shutter release. Your Canon Rebel uses the Canon EF mount and although I am not familiar with your camera it may also use the Canon EFs mount. Out of curiosity I did a quick scan on Ebay and found 11 Canon 70-300mm f4-5.6 EF lenses listed with a "Buy Now" price ranging from $119 to $189 ( avg was $139). I also found a couple Sigma 70-300mm f4-5.6 with canon EF mounts for $129 and if you are willing to go through the bidding procedures I saw a couple that went as cheap as $65+S&H. I am attaching some photos that i took with my Pentax ist DL (6.2mp) DSLR with a Sigma 70=300mm f 4-5.6 manual focus lens.

Just bought new glasses at Zenni. They're not bad, but not the quality I got at Sam's Club. Progressive lenses, anti-glare coating, clip-on sun glasses and new frames for $110 is a good deal for a backup pair. last pair at Sam's Club was $250, and the optometrist's office it was $400 + two years before. I call shenanigans on the story about the upside-down lenses. Even as a child getting glasses for the first time, I would have known if the glasses made things **worse.** As someone else pointed out, if one's eyes could adjust that much, we'd just exercise until we didn't need glasses, wouldn't we? In a former life, I had an optician that griped about me buying contact lenses *not through him* and told me it was illegal (sometime in the early 1980s). It would have been easier to purchase through him, but his office was so disorganized it always took multiple trips to get the right ones. Last time I went, I bought the one box for each eye, and went home to order them through the internet.

I know it's an old post-- but the current posters were writing about the same problem. Sorry, i was mobile and wasn't completely clear. I have progressives that only cover a limited range.. from reading to about 12 f away. These don't serve ALL my needs but they allow me to look up from my computer and see a person talking to me.. or to be in a meeting and read my laptop as well as the projected screen and the person sitting down the table. Two months ago, i had a pair of near glasses for my laptop and a far pair for the projection screen. I had nothing that would allow me to clearly see someone acrossthe table from me. I couldn't clean my house well because i couldn't see the floor well. My other (unrelated) eye issues prevented me from getting progressives right away so suffered through it for a year. I sat with my optician (my prescription was in hand from my ophthalmologist) and we talked about my needs and priorities. For ME, i was 1. I really needed the computer range -- to be dead center/looking ahead (my work monitors are set at exactly this height. Yours may vary) and at arm's length. 2. I needed to be able to lead a meeting while projecting on a screen. I needed to be able to SEE the screen and read small text on it.. and i needed to be able to look at each person around the table and see them clearly. 3. I needed to be able to read my notes/text on paper on the desk. This was the lowest priority because most of my reading is on a screen. Based on my prescription -- which is just like yours. A prescripion with a correction for near. (I think that's what it is.. my actual prescription is at work). It was my optician and the lab that used that to determine what focal lengths were where on my lenses to best fit my needs. Two other factors were important: 1. Lens Choice - my optician spent a lot of time finding the right lens -- lots of manufacturers make them but they have different ranges. Mine needed to give me the most range for my office needs. It also had to accomodate my prescription which is tricky 2. Digital Lab - it costs more but using the digital lab to combine my prescription needs AND to determine the graduation of the prescription (which is what makes them progressive) was highly recommended to me. It paid off. I had zero adjustment period. I was immediately able to see and adjust to where i needed to look for what. I was amazed that it wasn't just a top down progression, it also had lateral range. I could look off to my side and STILL see clearly. This was very important to me as i work on two monitors and i always have smeone sitting to my side. I use these glasses 85% of the time-- they work great at work and at home. I cannot walk about in them as well (though i can walk about).. and i can't drive with them. The lenses they used for me are Shamir (I don't know which model). They may not be the best for you but they were the best for my needs and my tricky prescription. I don't know what lab they used -- but it wasn't one of the mall eyeglass shops so it was an independent lab. Hope this helps give you hope.

theclose, this is my second pair of LaFonts. I love the first pair, way more colorful than I would have chosen if others hadn't talked me into it. The new ones are more sedate. I'm not a wacky glasses person. I still think glasses shouldn't cost so much. I'm not a frame snob and would have gladly gotten something for 1/4 the price at Costco if I found something I liked or if someone had actually gotten up off their a$$ and offered to help me find something I liked.