European trains are the best.

I would go to either B&H or Adorama and look at remote releases. They should list the camera bodies that each one works with, OR call them during business hours and talk to one of their sales people. They will answer all of your questions and get you ones that work with your particular camera. They have helped me countless times.

Rent the lens for a couple of reasons. First, and probably most important, you will be shooting with a body you are already familiar with. You know what the buttons do and to change a setting you won't have to hunt to find the right button, switch or dial. Secondly, you can evaluate the lens better for purchase later because you already know the quality of the images it produces with your current lens(es), so if the quality of the images changes, it is because of the lens, not the camera. I won't get into the issue of which lens to rent because each of them have pluses and minuses and it will come down to which one you feel more comfortable with. Have fun.

Because you were shooting a live critter, a 100mm macro would not have helped because you get would have gotten too close and scared the bee away. Because of my sports lens inventory (rodeos and car races), I will put a 1.4x teleconverter on my 70-200 f2.8 and then add a 12mm or 25mm extension tube to really shallow up the depth of field. If you have a non-pro 70-300mm f4.5-5.6 consumer grade lens (today's consumer grade lenses are pretty good) you might try a 12mm extension tube (or at 300mm the depth of field might have been shallow enough to get the blurred background you were looking for). Since there are no optical elements involved, extension tubes are not very expensive and can give you some very unique shots. Remember that the longer the focal length (assuming the same aperture), the shallower the depth of field, so if you want to get the background to be blurred out and you are working with a zoom lens, then zoom it all the way out. Good luck.

Unless you have a professional lens that is very sharp, then I wouldn't recommend any TC. I have a Canon 70-200 f2.8L IS lens and I use both a Canon 1.4x and 2x on it and the sharpness is very good with the 1.4x and pretty good with the 2x. I have also gone a bit nuts and used both converters stacked on the lens at the same time. It was an interesting experiment, but pretty soft, and you have to have a camera that AF will work at f8 or you will have to manually focus and be using a rock solid tripod with a remote shutter release. For sports photography (specifically rodeo and sports car racing, in my case) the 1.4x on the 70-200 was wonderful at both types of events, giving me the perfect focal lengths and things were sharp. In sunny, daylight conditions I could get 1/1000 second shutter speeds or more (although at car races I shoot at 1/250 for wheel rotation blur and background horizontal blur to accentuate the sense of speed). At rodeos I needed all the speed I could get. Bulls don't move in any consistent direction so panning doesn't help with them. I usually shot at ISO 800 with a Canon 7D II (20MP). Long ago I used Tamron "Pro" teleconverters and they were quite a bit softer on the 70-200. I would say to stay away from non-original manufacturer TC's because they will be too soft. The original manufacturer TC's can only be used with certain (not all) of their own professional series lenses because of the protrusion of the TC that actually goes inside the lens body. If you ignore that you can damage the TC and the lens while zooming or focusing. I won't get into the cropping thing except to say you better be working with a high-quality camera and the cropping better be minimal to get a good image unless you are working with 36 to 50+ megapixels. That is my real-world experience.

Never bought a camera from them but have bought several lenses and they were always in better condition than I thought they would be. I had a problem with one lens after it was about three months out of warranty. The flat rate for the repair was about $200 or close to that. I asked if they could do something a little better than that since I had bought several things from them. The next day, they called and said they would replace the lens for free and sent the new one back to me "next day air" because I was shooting an event that weekend. That tells you a lot about how they operate.

Love those Pitts Specials. As a pilot, I always wanted to get one and get into aerobatics to sharpen my skills. A Cessna 150 aerobat just doesn't get the job done. Great shots. 400mm?

I shoot Canon, and use a 70-200 f2.8 L IS. I have used it for night time football games, rodeos in indoor arenas (and outdoors at night) and have taken, literally, thousands of shots of the rodeos with that lens. When I stopped shooting from the arena floor, with angry bulls chasing me around occasionally, I started using it with a 1.4TC and it did pretty well. I found that using the most powerful flash that Canon made at the time (GN 197), with a "Better Beamer" flash extender, upped the number of "keepers" and I could shoot from outside the fence. I had to set the camera to "high speed synch" which is available on most digital SLR's and set the camera up on ISO 800 and I could get shutter speeds of 1/800 of a second. This was over ten years ago and I still am amazed at the shots I got. If the action is moving towards the camera, you will get sharper shots than if it is moving across the frame. It is also better if you can shoot standing at ground level, ideally along the sidelines for a more natural looking shot. Just make sure you get out of the way when the action heads in your direction. I have gotten knocked down a couple of times when I was concentrating on "getting the shot" both at football games and at bull riding events, luckily with no injuries, although one camera got crushed under the foot of an angry bull. The 70-200 lens was just fine though. Those f2.8's are built like a tank. That is my ten cents.

the simple explanation is that the smaller aperture only allows the light coming through center of the lens to be used to make the image, and that light is not being bent as much as light coming from the outer edges of lens, where that light from those outer edges is being bent a lot more and traveling a longer distance.

I did start out cheap ($50) and that was a joke. I kept it to hold an off-camera flash. My current rig is a Manfrotto 057 tripod with a 057 ball head. It is good for 30lbs, which is a bit of overkill, even for my 100-400 Canon with 7D II body, but I don't worry about things not being steady. It is solid as a rock, but it should be for $1000. It is carbon fiber, but as I upgrade to bigger, longer, heavier stuff I won't have to upgrade unless I want to go with a gimbal head and then, it will only be the head. I have had it for four or five years (I'm old and cannot remember these trivial things) and never had a problem, even in 15-20 knot winds. Now that we all have all confused you, talk to someone at a real, quality camera store (B&H, Adorama) and they will steer you straight. I don't buy from places on Ebay. I want someone I can trust that the pro's go to.

Suggestion. Call B&H or Adorama and tell them what camera/lens setup you are using and the reason why you want to get a tripod and your proposed budget. They have good knowledgeable people who are all real photographers and know what tripods will get the job done for you without spending an arm and a leg. I would think $200 would be the top for what you need. BUT, if you plan to get more serious with your photography and buy longer, heavier lenses or a heavier camera, it will be cheaper in the long run to buy a heavier-duty tripod now, rather than a light-duty tripod now and then a second tripod later. For now, I would think an aluminum tripod would be just fine, unless having a lighter weight tripod is of critical importance for you. Good luck.

I am not sure why you are asking a question since you don't seem to have any problem that needs "fixing". I know that I always have taken the cards out of my camera and uploaded the images onto two separate external hard drives, the put the card back in the camera and then "reformatted the card right away. The only reason I reformat it right away is so I don't go out to shoot a week or so down the road and find that I am out of room on my card because I didn't reformat it to get rid of the old stuff. I reformat the card in the camera because that is what the camera manufacturer recommends (Canon 7D, Canon 7D II and an ancient Canon 20D). I have never had a memory card problem in spite of running them through the washer and dryer a couple of times when I left them in a shirt or a pants pocket. That is what convinced to go with a digital boot drive in my computer.

I would go straight to Nikon's website, and look under "deals". If the D7100 is not a current camera, there will be something close to it in specs that is listed under "refurbs". They all come with a good warranty and you can buy "body only" and then get a "refurb" lens of your choice or see if there is a "refurb" kit that works for your friend. Buying it directly from the manufacturer, means it will be in essentially "new" condition. All of my current gear was bought either "refurb" or used (from KEH or B&H) and I have had no problems over the years (Canon 7d, 7d II, 70-200 f2.8 L IS, 24-105 f4 L IS, 17-40 f4 L and teleconverters, etc.). I stay with these guys and don't bother with ebay. I want a vendor who has a long track record and a good reputation.

Been shooting digital since 2004 and up until I bought my Canon 7d II a few years ago, never had two slots. I have never lost an image due to card failure, even though I have run them through the washer and dryer a couple of times and have a dent in one of my 64GB CF cards. For a true professional, I can see the advantage of having every image backed up on 2 cards, but these things are so reliable now (both the cameras and the cards), that for the vast majority of us it is a moot point.

If you are really looking for a 17" wide and would like to save money, I would look at manufacturer's "refurbished" printers on their websites. My last two Epson photo printers were purchased that way - an Epson R1800 that worked for more years than I wanted it to (I wanted an excuse to buy a different, larger printer) and its replacement, an Epson 3880 (17" wide). I still use the 3880 to this day, more than 5 years later and bought it for about $800 when the retail price was $1295. It came with all the same stuff as the new one including a 1 year warranty. It just doesn't come in the pretty retail box, but comes instead in a brown corrugated box, but who cares about the box, right? It has worked perfectly ever since. I am almost to the point where I wish it would die because I want to buy a new printer, but it keeps doing great prints and saving me from myself.