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 on: April 11, 2014, 06:24:44 PM 
Started by KeithB - Last post by bmpress
I just got back from a photo trip to the Everglades National Park near Homestead and can say that gators are numerous in natural locations where you can shoot pics as close as ten feet. I used a 70-200 and never needed more reach. I was always safe.,  but if you choose to walk in wild locations near water you put yourself at great risk.   

 on: April 01, 2014, 11:26:44 PM 
Started by KeithB - Last post by Bob Atkins
You're in luck with the AF then! The IS will work, but the camera will think it's a 300mm lens and so it won't be using quite the right stabilization parameters. Should be better than no IS at all though. A tripod would be the best support option of course, even a lightweight travel tripod (or monopod). I use my Velbon 343e travel tripod quite a lot (see review below). It's no longer available, but there are similar options out there.

 on: April 01, 2014, 04:00:35 PM 
Started by KeithB - Last post by KeithB
Actually, my AF seems to work fine. But thanks for the other suggestions, I will take the 1.4X and try to take some comparison shots. I think the main problem with sharpness is that the IS won't be as effective at 1.4X, so bright sunny days will be the ticket.

 on: March 31, 2014, 05:31:47 PM 
Started by KeithB - Last post by Bob Atkins
When I did the test of the 70-300IS I found that center resolution was better with the 1.4x than upsizing the image without the TC.

See for an example

AF may be either non existent or flaky, depending on the camera, but that's something you can test before you go on the trip. You might get AF at f8 on an APS-C body by using contrast detection in Live View. It's worth testing.

Personally I'd probably shoot some shots at 300mm, then add the TC for a few more shots if I had time. That way you get to pick the shots that work out best.

 on: March 31, 2014, 02:41:39 PM 
Started by KeithB - Last post by KeithB
I have the Canon 70-300mm telephoto soom, and I am going to Florida in a few months. I want to get good images of gators and things (but I don't want to get too close!). I also have a Tamron 1.4 teleconverter.

So should I stick with the lens by itself or add the teleconverter? I did the quick test test that Bob laid out with the test patterns in the center and corners, and found that, yes, you really need a calm day and tripod for that test. 8^)

It was pretty clear that there is more chromatic aberration with the converter. (If you use the white pegboard for Bob's test, the holes make for a good CA test pattern).

I remember from Bob's article from way back that it is kind of a wash, so I was looking for any more thoughts or suggestions.

 on: March 27, 2014, 02:40:06 PM 
Started by klindup - Last post by Bob Atkins
I don't think there's anything wrong with the Sigma macro. but I'd also look at the Canon 100/2.8 macro if you're concerned about price or the Canon 100/2.8L IS USM macro if you don't mind spending a few more dollars. The new Canon L macro is especially nice since it has multi axis IS with gyros and accelerometers which optimize performance in the macro range by compensating for both translational and rotational camera movement. As far as I know the Sigma just has the normal rotation compensation IS (OS), which is ineffective at close macro distances, though would be useful for handheld portrait work of course.

Canon 100/2.8 USM Macro - $599

Canon 100/2.8L IS USM - $929 after $100 mail-in rebate (price drops when you add it to the shopping cart as it's lower than Canon's Minimum Advertised Price)

Sigma 105/2.8 OS - $669

All three lenses are very sharp especially since you are very likely to be stopped down when shooting macro to get DOF.

 on: March 22, 2014, 01:52:19 AM 
Started by klindup - Last post by klindup
I am looking to buy a 100mm macro lens, mainly for taking photographs of flowers, but also for head and shoulder portraits.  The reviews that I have read suggest that the Sigma 105mm 2.8 is the one to go for.  The only downside is that it is slower at focusing than the Canon 100mm 2.8.  If that is the only fault then I am not concerned because it is likely that I will be using manual focusing with live view and using a focusing rail, possibly even focus stacking.  Have any members of this group got experience of 100mm macro lenses.  I do not want to buy a lens only to discover that I should have bought a different one.
Ken Lindup

 on: March 17, 2014, 09:37:15 AM 
Started by Johnny - Last post by Johnny
Installed the latest version of DPP, v3.14.15.0 and now DPP loads fast once again. Supports Windows 8.1.

 on: March 16, 2014, 05:15:40 PM 
Started by klindup - Last post by klindup
Thanks Bob
The speaker  is well informed on matters photographic but offered no evidence for his concern about damaging the camera.  I shall continue to use a USB connection to download images. 

 on: March 16, 2014, 03:28:41 PM 
Started by klindup - Last post by Bob Atkins
What qualifications did the speaker have and what evidence did he present to back up his theory?

The computer may or may not be grounded (or "earthed" in UK terminology). Anything running off a 2 pin plug can't be grounded, but if it has a 3 pin plug it can be (and usually would be).

We plug lots and lots of USB devices into PCs. printers, scanners, routers, modems, disk drives, iPods and cameras to name a few. If there was a chance of damaging any of them we'd have lots of complaints and the engineers who designed the systems would be out of a job.

Looks to me like a USB makes a chassis (ground) to chassis(ground) connection first, before any signal lines get connected anyway.

So I'd say the speaker didn't have a very well informed opinion. I don't think there is any danger connecting a camera to a PC due to  "static" issues.

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