Another guess the tree series

[Cyclops]

with some info of interest to Rik!

This is a tiny cone that I found on my travels, and today I decided to shoot up close. This time though I had a new plan, thanks to Rik!
You see I wanted to actually work out what field of view, and thus what magnification, I was getting with my set up.
But to start with I used a ruler to see how much I was seeing at each magnification, and at lifesize(1:1 as marked on the macro lens)
Here, at 3.5X(28mm reversed onto 100mm) with a field of view of 3.5mm:


Next, with the Pentax 50 reversed, this should give me 2X, and indeed I got a field of view of around 8mm(bear in mind my viewfinder only shows 95% of the FOV)


Finally,the whole thing as seen at lifesize with just the macro lens set to 1:1 (FOV=23mm)

(You can see the FOV in this link)
http://img.photobucket.com/albums/v11/D ... ale_1X.jpg

That last one is quite special too as, with the help of a cardboard tube, slightly modified, i was able to use the pop up flash, saving the battery!

[rjlittlefield]

Nice series!

Looking at that image contained in your last link, I see that your macro lens is giving you exactly what the manufacturer says. The FOV as shown in the image is 22.7 mm, and your sensor width is 22.7 mm, so magnification = 22.7/22.7 = 1X, exactly what it ought to be at 1:1.

I'm having a bit more trouble matching up some other numbers you mention with what I see in the photos and what the lens combos are.

For example I can overlay your first picture on your third, then scale and rotate it so that details of the cone line up. When I do that, I get a magnification of 3.7X, not far off the 3.5X predicted. But magnification of 3.7X corresponds to a field width of 6.1 mm, not the 3.5mm that you mention.

If I do the same thing with your second image (overlay it on the third), then I get a magnification of 2.5X and a field width of 9.1 mm, not too far off what you saw.

Can you take, upload, and link pictures of the ruler through the combos, just like you did with the macro lens at 1:1? I'd be interested to see what they look like.

--Rik

[Cyclops]

If I do the same thing with your second image (overlay it on the third), then I get a magnification of 2.5X and a field width of 9.1 mm, not too far off what you saw.

Can you take, upload, and link pictures of the ruler through the combos, just like you did with the macro lens at 1:1? I'd be interested to see what they look like.

--Rik

Thanks Rik.
I could do that but I need a smaller ruler. The one I used is a big heavy job and I had nothing to clamp it down with, so when using the higher magnifications the lens is very close to the ruler and so holding it is very hit and miss!

[rjlittlefield]

Hhmm... I often set the camera on a table and either prop the ruler in front of it, or just hold the ruler in my hand with my hand resting on the table. The pictures don't need to be perfectly crisp, just so the marks are roughly in focus. It's easier to get some of the marks in focus if you tip the ruler backward a little, so the bottom of each mark is a little closer to the camera than the top is. Come to think of it, it's easier to prop that way too.

--Rik

[Cyclops]

Yea I might try later once I put matthew to bed

[Ken Ramos]

Looks to be the cone of an Alder tree. I have Alder thickets down by the creek below my apartment.

[Cyclops]

Looks to be the cone of an Alder tree. I have Alder thickets down by the creek below my apartment.

Yep, its Alnus glutinosa(I presume its the native species anyway!)

[Ken Ramos]

If I am not mistaken, we have only one native species of Alder here, the rest came over from Europe, along with BMW's, Volkswagons, etc.

[Cyclops]

If I am not mistaken, we have only one native species of Alder here, the rest came over from Europe, along with BMW's, Volkswagons, etc.

I'm not sure Ken if our Alder is found in the US too,will have to check