Modify 70-300mm macro lens to focus at 0.95m (Tamron/Sigma/Quantaray compatible)

I discovered this modification by accident in 2008 when I want to clean my Sigma 70-300mm II. I discovered that the lens is capable of using macro mode at all focal range, and the manufacture hide this feature by adding a ‘limiter’ button. Later on I discovered Tamron 70-300mm, Sigma 70-300mm I as well as a Nikon mount all use the same mechanism.

This post is for your reference only, PERFORM THIS MODIFICATION AT YOUR OWN RISK, I hold no responsibility if you damage your lens. Anyway, let’s begin 🙂

From left to right: Sigma 70-300mm DL Sigma 70-300mm II Tamron 70-300mm
From left to right:
Sigma 70-300mm DL
Sigma 70-300mm II
Tamron 70-300mm

Index:

1) Introduction and samples

2) Tamron tutorial (under construction, video only)

3) Sigma II tutorial

4) Sigma I tutorial


1) Introduction and samples

_MG_2172b
‘Face-to-face’, shot on 21 Mar 2008.
Canon EOS 40D
Sigma 70-300mm II
1/400 F10
ISO1600
Focal length 70mm
Click to enlarge, shot taken at about 1m away from object.
Canon EOS 5D mk II
Tamron 70-300mm
1/2 F5.6
ISO 160
Focal length 81mm
EOS 5D mk II 1/500 F8 ISO 1250 Focal length 119mm
Canon EOS 5D mk II
Sigma 70-300mm II
1/500 F8
ISO 1250
Focal length 119mm

2) Tamron tutorial

Full tutorial coming soon, meanwhile this is the older video:

PERFORM THIS MODIFICATION AT YOUR OWN RISK I said.
After I made that video I receive both positive feedback and negative feedback on missing out some steps, so I made a new video for Tamron:


3) Sigma II tutorial

This particular lens is my very first attempt to DIY lens disassembly/repair/clean in 2008. I still remember how much pain and stress I went through trying to figure everything out… anyway, I managed to pick up this version of the lens again recently in the flea market, just for your benefits.

IMG_6524s
The Sigma 70-300mm macro II (3rd batch I think, the first batch was with the ‘droplets hardened’ coating, 2nd batch is the poor quality rough coating that comes off after some times)

IMG_6587s

The Sigma is significantly more difficult than the Tamron because you need to desolder, definitely not for beginners. Here’s what you WILL need:

1) Solder gun and iron
2) + and – screw drivers (obviously), however a big and tiny + screw driver
3) Cutter/Dremel/file/sandpaper/anything that cuts

.. and optional but good to have:

4) masking tape
5) solder ‘sucker’
6) oil and cleaning paper in case you like to service the lens at the same time.

IMG_6527s
1) removed the tiny screws that holds the communication port. 2) remove the 3 screws

After removing those, proceed with removing the mount plate (sorry no pics, straightforward enough).

IMG_6528s
I said this is not for beginner. If this scares you, stop and put it back. If you like to attempt and learn new things, a rule of thumb is: proceed with cautious (some old lens has stupid springs that jumps out if you are not careful), take pictures if you can, in case you forget how it looks like. Make sure you remember how to assemble back at any point, so you can give up just before you decided that you can’t continue anymore.
IMG_6529s
Upon removing the copper washers, continue to remove the 4 silver screws. When you take this part out, becareful at the AF/MF button which links to the gears. You might need to wriggle a little.
IMG_6534
Desolder the 2 areas as marked, (the picture showed the desoldered right portion). Though it is possible to disassemble by only desolder one of these, but you may risk damaging the cable so I suggest desolder these two.
IMG_6534-2
After desolder, take out the black screws so you can remove the electronics assembly.
IMG_6535s
You should end up with this.
IMG_6533s
You will see 4 hidden bigger screws under the electronic, take these out. You can then remove the barrel from the lens group.
Now you should have these two major parts. If you only want to modify, take the barrel to the right. If you want to go in advance to reach further of the lens and to clean the elements, take the left which I will share later.
Now you should have these two major parts. If you only want to modify, take the barrel to the right. If you want to go in advance to reach further of the lens and to clean the elements, take the left which I will share later.

FOR THE MODIFICATION

Now you will find that this empty barrel is a lie itself. You have this empty barrel and the button doesn’t link to any part of the lens group! What sorcery is this %*@($* button? Now we will remove this once and for all.

This is a bit tricky. See this screws, you do not have to remove it completely. Unscrews it however. This act as a stopper to prevent the lens over turn. Unscrew to the point you can over turn.
This is a bit tricky. See this screws, you do not have to remove it completely. Unscrews it however. This act as a stopper to prevent the lens over turn. Unscrew to the point you can over turn.
IMG_6539s
Twist the barrel until you see the thing sticks out become visible.
IMG_6540s
.. and now you can remove the barrel from this hole!
Now you see that little silver thing, that's the part we want to remove. On my first try in 2008 I used a cutter and filer. This time round I attempted to use a grinder/Dremel. Bad exampe... I will explain what happened..
Now you see that little silver thing, that’s the part we want to remove. On my first try in 2008 I used a cutter and filer. This time round I attempted to use a grinder/Dremel. Bad exampe… I will explain what happened..
IMG_6547s
The high speed blade heats up and the metal sinks into the melted plastic. Well, I have no choice but to even out the surface. Still works.
This is what it should look like from the side. Make sure that it does not obstruct anything when you switch the button.
This is what it should look like from the side. Make sure that it does not obstruct anything when you switch the button.

.. and now, resemble back and you have your own modified Sigma 70-300mm macro lens!

So, if you want to dismantle further, here’s the advance:

IMG_6553s
For the benefit of newbies on your first attempt, many lenses out there can fit in at different angle and also to calibrate the focusing distance. So a good practice is, make marking or take photo or do both at every steps so you remember which is the correct position. For this stance, this is the perfect example. You may realise that the whole element can rotate out.
IMG_6554s
.. like this..
IMG_6555s
Now, if you miss the correct groove and put it back, notice the circular thing that sticks out from the barrel.. it’s misaligned from the first picture. It may seem like it fits BUT YOU WILL NEVER ASSEMBLE EVERYTHING BACK IN GOOD WORKING CONDITION ANYMORE. Now imaging that back in 2008 I learnt it the hard way without any guidance T_T … I trial and error until everything fits.. also by studying every grooves and fittings..

So, forget about the bad example above, make marking and let’s continue.

IMG_6566s
Picture shows removed silver screw. There’s 3 of them on the same height. Remove them slowly..
IMG_6567s
Slowly pulls out, you will see underneath there’s 3 gold colored cams. Remember to make marking again at where these 2 barrels are fitting in for each other so you know how to put it back. Why does this picture has the circuit board on top? This is my another attempt after re-soldering back the board, attempt if the lens can still be disassemble with minimum de-soldering. This is NOT ADVISABLE as it will keep dangling and risk damage the cable.
IMG_6569ss
Now you will see this professionally doodled image and let me explain what is this masterpiece artwork. You see many grooves and cam systems, to put things easy, there are 3 layers with 3 repeating pattern across the barrels, this is design to tell how the elements move when you ‘zoom’. I layered them 1 to 3.

 Layer 1 : These 3 cams holds one glass element. You need not remove this even if you need to clean it, because you can access it when you remove ‘2’ and ‘3’, and also because you can’t even pull it out by removing only ‘1’.

Layer 2: Marked in purple, this is the most important layer that holds your last assembly. When you put it back, align it to the point when you can see the long groove where you can find the screw hole.

Layer 3: This is for the gold cam that you removed just now, just don’t mix this up with layer 2.

So if you remove layer 2, you will end up with this final element. If you want to clean inside, simple hold and turn the glass at the right. That glass can be remove without going through all these steps. This advance cleaning is mainly for the inner elements.
So if you remove layer 2, you will end up with this final element. If you want to clean inside, simple hold and turn the glass at the right. That glass can be remove without going through all these steps. This advance cleaning is mainly for the inner elements.

So that’s it! I assume if you can follow the steps all the way, you should have no problem assemble back.

If you find these information interesting, please leave your comments below or visit me on my facebook page.


4) Sigma I tutorial

I know not the history of this lens, I acquired this semi-faulty lens at Tokyo for 500 yen.
I know not the history of this lens, I acquired this semi-faulty lens at Tokyo for 500 yen.
This is the EASIEST to modify of all. Simply remove the button here.
This is the EASIEST to modify of all. Simply remove the button here.

sIMG_0063Technically you can remove the entire button BUT, if you study the lens carefully.. the lens front element is installed by twisting the barrel and stop by this same button. Meaning, if you remove this, the entire element may drop out completely. One method is remove only the lower pin, and keep the upper pin to stop the lens if necessary.

3 Oct 2015 update:

Until recently (7 years after this DIY) I finally thought I should monetize on this… I have not make any profit with these DIYs, not to mention many failed DIYs that left me with dead cameras/lenses.. so please support me by clicking below! Any amount is appreciated!

$1 – Aah… coffee
<$5 – Mmm… lunch meal
<$10 – Woo… ramen
<$25 – Waa… steak
>$50 – WOW! Thank you!

btn_donate_pp_142x27

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